**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.489 2008/07/08 22:28:49 shane Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
      SelectDest dest;
      Table *pSelTab;

      sqlite3VdbeAddOp3(v, OP_OpenWrite, 1, pParse->regRoot, iDb);
      sqlite3VdbeChangeP5(v, 1);
      pParse->nTab = 2;
      sqlite3SelectDestInit(&dest, SRT_Table, 1);
      sqlite3Select(pParse, pSelect, &dest, 0, 0, 0, 0);
      sqlite3VdbeAddOp1(v, OP_Close, 1);
      if( pParse->nErr==0 ){
        pSelTab = sqlite3ResultSetOfSelect(pParse, 0, pSelect);
        if( pSelTab==0 ) return;
        assert( p->aCol==0 );
        p->nCol = pSelTab->nCol;
        p->aCol = pSelTab->aCol;

**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**
** $Id: build.c,v 1.490 2008/07/08 23:40:20 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called when a new SQL statement is beginning to
** be parsed.  Initialize the pParse structure as needed.
................................................................................
      SelectDest dest;
      Table *pSelTab;

      sqlite3VdbeAddOp3(v, OP_OpenWrite, 1, pParse->regRoot, iDb);
      sqlite3VdbeChangeP5(v, 1);
      pParse->nTab = 2;
      sqlite3SelectDestInit(&dest, SRT_Table, 1);
      sqlite3Select(pParse, pSelect, &dest, 0, 0, 0);
      sqlite3VdbeAddOp1(v, OP_Close, 1);
      if( pParse->nErr==0 ){
        pSelTab = sqlite3ResultSetOfSelect(pParse, 0, pSelect);
        if( pSelTab==0 ) return;
        assert( p->aCol==0 );
        p->nCol = pSelTab->nCol;
        p->aCol = pSelTab->aCol;

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.169 2008/04/28 18:46:43 drh Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
    SrcList *pFrom;
    
    pWhere = sqlite3ExprDup(db, pWhere);
    pFrom = sqlite3SrcListAppendFromTerm(pParse, 0, 0, 0, 0, pDup, 0, 0);
    pDup = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);
  }
  sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
  sqlite3Select(pParse, pDup, &dest, 0, 0, 0, 0);
  sqlite3SelectDelete(pDup);
}
#endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */


/*
** Generate code for a DELETE FROM statement.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** in order to generate code for DELETE FROM statements.
**
** $Id: delete.c,v 1.170 2008/07/08 23:40:20 drh Exp $
*/
#include "sqliteInt.h"

/*
** Look up every table that is named in pSrc.  If any table is not found,
** add an error message to pParse->zErrMsg and return NULL.  If all tables
** are found, return a pointer to the last table.
................................................................................
    SrcList *pFrom;
    
    pWhere = sqlite3ExprDup(db, pWhere);
    pFrom = sqlite3SrcListAppendFromTerm(pParse, 0, 0, 0, 0, pDup, 0, 0);
    pDup = sqlite3SelectNew(pParse, 0, pFrom, pWhere, 0, 0, 0, 0, 0, 0);
  }
  sqlite3SelectDestInit(&dest, SRT_EphemTab, iCur);
  sqlite3Select(pParse, pDup, &dest, 0, 0, 0);
  sqlite3SelectDelete(pDup);
}
#endif /* !defined(SQLITE_OMIT_VIEW) && !defined(SQLITE_OMIT_TRIGGER) */


/*
** Generate code for a DELETE FROM statement.

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.383 2008/07/04 09:41:39 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
        */
        SelectDest dest;
        ExprList *pEList;

        sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
        dest.affinity = (int)affinity;
        assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
        if( sqlite3Select(pParse, pExpr->pSelect, &dest, 0, 0, 0, 0) ){
          return;
        }
        pEList = pExpr->pSelect->pEList;
        if( pEList && pEList->nExpr>0 ){ 
          keyInfo.aColl[0] = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft,
              pEList->a[0].pExpr);
        }
................................................................................
      }else{
        dest.eDest = SRT_Exists;
        sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iParm);
        VdbeComment((v, "Init EXISTS result"));
      }
      sqlite3ExprDelete(pSel->pLimit);
      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
      if( sqlite3Select(pParse, pSel, &dest, 0, 0, 0, 0) ){
        return;
      }
      pExpr->iColumn = dest.iParm;
      break;
    }
  }

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.384 2008/07/08 23:40:20 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
        */
        SelectDest dest;
        ExprList *pEList;

        sqlite3SelectDestInit(&dest, SRT_Set, pExpr->iTable);
        dest.affinity = (int)affinity;
        assert( (pExpr->iTable&0x0000FFFF)==pExpr->iTable );
        if( sqlite3Select(pParse, pExpr->pSelect, &dest, 0, 0, 0) ){
          return;
        }
        pEList = pExpr->pSelect->pEList;
        if( pEList && pEList->nExpr>0 ){ 
          keyInfo.aColl[0] = sqlite3BinaryCompareCollSeq(pParse, pExpr->pLeft,
              pEList->a[0].pExpr);
        }
................................................................................
      }else{
        dest.eDest = SRT_Exists;
        sqlite3VdbeAddOp2(v, OP_Integer, 0, dest.iParm);
        VdbeComment((v, "Init EXISTS result"));
      }
      sqlite3ExprDelete(pSel->pLimit);
      pSel->pLimit = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &one);
      if( sqlite3Select(pParse, pSel, &dest, 0, 0, 0) ){
        return;
      }
      pExpr->iColumn = dest.iParm;
      break;
    }
  }

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.246 2008/07/08 22:28:49 shane Exp $
*/
#include "sqliteInt.h"

/*
** Set P4 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
    sqlite3SelectDestInit(&dest, SRT_Coroutine, ++pParse->nMem);
    addrSelect = sqlite3VdbeCurrentAddr(v)+2;
    sqlite3VdbeAddOp2(v, OP_Integer, addrSelect-1, dest.iParm);
    j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
    VdbeComment((v, "Jump over SELECT coroutine"));

    /* Resolve the expressions in the SELECT statement and execute it. */
    rc = sqlite3Select(pParse, pSelect, &dest, 0, 0, 0, 0);
    if( rc || pParse->nErr || db->mallocFailed ){
      goto insert_cleanup;
    }
    sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof);         /* EOF <- 1 */
    sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);   /* yield X */
    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
    VdbeComment((v, "End of SELECT coroutine"));

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle INSERT statements in SQLite.
**
** $Id: insert.c,v 1.247 2008/07/08 23:40:20 drh Exp $
*/
#include "sqliteInt.h"

/*
** Set P4 of the most recently inserted opcode to a column affinity
** string for index pIdx. A column affinity string has one character
** for each column in the table, according to the affinity of the column:
................................................................................
    sqlite3SelectDestInit(&dest, SRT_Coroutine, ++pParse->nMem);
    addrSelect = sqlite3VdbeCurrentAddr(v)+2;
    sqlite3VdbeAddOp2(v, OP_Integer, addrSelect-1, dest.iParm);
    j1 = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0);
    VdbeComment((v, "Jump over SELECT coroutine"));

    /* Resolve the expressions in the SELECT statement and execute it. */
    rc = sqlite3Select(pParse, pSelect, &dest, 0, 0, 0);
    if( rc || pParse->nErr || db->mallocFailed ){
      goto insert_cleanup;
    }
    sqlite3VdbeAddOp2(v, OP_Integer, 1, regEof);         /* EOF <- 1 */
    sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);   /* yield X */
    sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_INTERNAL, OE_Abort);
    VdbeComment((v, "End of SELECT coroutine"));

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.244 2008/06/05 16:47:39 danielk1977 Exp $
*/

// All token codes are small integers with #defines that begin with "TK_"
%token_prefix TK_

// The type of the data attached to each token is Token.  This is also the
// default type for non-terminals.
................................................................................
}
%endif  SQLITE_OMIT_VIEW

//////////////////////// The SELECT statement /////////////////////////////////
//
cmd ::= select(X).  {
  SelectDest dest = {SRT_Callback, 0, 0, 0, 0};
  sqlite3Select(pParse, X, &dest, 0, 0, 0, 0);
  sqlite3SelectDelete(X);
}

%type select {Select*}
%destructor select {sqlite3SelectDelete($$);}
%type oneselect {Select*}
%destructor oneselect {sqlite3SelectDelete($$);}

**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
**
** @(#) $Id: parse.y,v 1.245 2008/07/08 23:40:20 drh Exp $
*/

// All token codes are small integers with #defines that begin with "TK_"
%token_prefix TK_

// The type of the data attached to each token is Token.  This is also the
// default type for non-terminals.
................................................................................
}
%endif  SQLITE_OMIT_VIEW

//////////////////////// The SELECT statement /////////////////////////////////
//
cmd ::= select(X).  {
  SelectDest dest = {SRT_Callback, 0, 0, 0, 0};
  sqlite3Select(pParse, X, &dest, 0, 0, 0);
  sqlite3SelectDelete(X);
}

%type select {Select*}
%destructor select {sqlite3SelectDelete($$);}
%type oneselect {Select*}
%destructor oneselect {sqlite3SelectDelete($$);}

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.450 2008/07/08 19:34:07 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
................................................................................
      break;
    }
  }
  if(
     (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
     (jointype & JT_ERROR)!=0
  ){
    const char *zSp1 = " ";
    const char *zSp2 = " ";
    if( pB==0 ){ zSp1++; }
    if( pC==0 ){ zSp2++; }
    sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
       "%T%s%T%s%T", pA, zSp1, pB, zSp2, pC);

    jointype = JT_INNER;
  }else if( jointype & JT_RIGHT ){
    sqlite3ErrorMsg(pParse, 
      "RIGHT and FULL OUTER JOINs are not currently supported");
    jointype = JT_INNER;
  }
  return jointype;
................................................................................
  ExprList *pEList,       /* List of values being extracted */
  int srcTab,             /* Pull data from this table */
  int nColumn,            /* Number of columns in the source table */
  ExprList *pOrderBy,     /* If not NULL, sort results using this key */
  int distinct,           /* If >=0, make sure results are distinct */
  SelectDest *pDest,      /* How to dispose of the results */
  int iContinue,          /* Jump here to continue with next row */
  int iBreak,             /* Jump here to break out of the inner loop */
  char *aff               /* affinity string if eDest is SRT_Union */
){
  Vdbe *v = pParse->pVdbe;
  int i;
  int hasDistinct;        /* True if the DISTINCT keyword is present */
  int regResult;              /* Start of memory holding result set */
  int eDest = pDest->eDest;   /* How to dispose of results */
  int iParm = pDest->iParm;   /* First argument to disposal method */
................................................................................
    ** table iParm.
    */
#ifndef SQLITE_OMIT_COMPOUND_SELECT
    case SRT_Union: {
      int r1;
      r1 = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
      if( aff ){
        sqlite3VdbeChangeP4(v, -1, aff, P4_STATIC);
      }
      sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
      sqlite3ReleaseTempReg(pParse, r1);
      break;
    }

    /* Construct a record from the query result, but instead of
    ** saving that record, use it as a key to delete elements from
................................................................................
      for(i=0; i<nColumn; i++){
        assert( regRow!=pDest->iMem+i );
        sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iMem+i);
      }
      if( eDest==SRT_Callback ){
        sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iMem, nColumn);
        sqlite3ExprCacheAffinityChange(pParse, pDest->iMem, nColumn);
      }else if( eDest==SRT_Coroutine ){
        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
      }
      break;
    }
    default: {
      /* Do nothing */
      break;
    }
  }
  sqlite3ReleaseTempReg(pParse, regRow);
  sqlite3ReleaseTempReg(pParse, regRowid);

  /* Jump to the end of the loop when the LIMIT is reached
  */
  if( p->iLimit ){
    sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
    sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, brk);
  }

  /* The bottom of the loop
  */
  sqlite3VdbeResolveLabel(v, cont);
  sqlite3VdbeAddOp2(v, OP_Next, iTab, addr);
  sqlite3VdbeResolveLabel(v, brk);
  if( eDest==SRT_Callback || eDest==SRT_Coroutine ){
................................................................................
      addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit);
      sqlite3VdbeAddOp2(v, OP_Integer, -1, iOffset+1);
      sqlite3VdbeJumpHere(v, addr1);
    }
  }
}

/*
** Allocate a virtual index to use for sorting.
*/
static void createSortingIndex(Parse *pParse, Select *p, ExprList *pOrderBy){
  if( pOrderBy ){
    int addr;
    assert( pOrderBy->iECursor==0 );
    pOrderBy->iECursor = pParse->nTab++;
    addr = sqlite3VdbeAddOp2(pParse->pVdbe, OP_OpenEphemeral,
                            pOrderBy->iECursor, pOrderBy->nExpr+1);
    assert( p->addrOpenEphm[2] == -1 );
    p->addrOpenEphm[2] = addr;
  }
}

#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** Return the appropriate collating sequence for the iCol-th column of
** the result set for the compound-select statement "p".  Return NULL if
** the column has no default collating sequence.
**
** The collating sequence for the compound select is taken from the
................................................................................
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */

/* Forward reference */
static int multiSelectOrderBy(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The right-most of SELECTs to be coded */
  SelectDest *pDest,    /* What to do with query results */
  char *aff             /* If eDest is SRT_Union, the affinity string */
);


#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** This routine is called to process a compound query form from
** two or more separate queries using UNION, UNION ALL, EXCEPT, or
................................................................................
**
** Notice that because of the way SQLite parses compound SELECTs, the
** individual selects always group from left to right.
*/
static int multiSelect(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The right-most of SELECTs to be coded */
  SelectDest *pDest,    /* What to do with query results */
  char *aff             /* If eDest is SRT_Union, the affinity string */
){
  int rc = SQLITE_OK;   /* Success code from a subroutine */
  Select *pPrior;       /* Another SELECT immediately to our left */
  Vdbe *v;              /* Generate code to this VDBE */
  int nCol;             /* Number of columns in the result set */
  ExprList *pOrderBy;   /* The ORDER BY clause on p */
  int aSetP2[2];        /* Set P2 value of these op to number of columns */
  int nSetP2 = 0;       /* Number of slots in aSetP2[] used */
  SelectDest dest;      /* Alternative data destination */
  Select *pDelete = 0;  /* Chain of simple selects to delete */

  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
................................................................................
  if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
    sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
      " do not have the same number of result columns", selectOpName(p->op));
    rc = 1;
    goto multi_select_end;
  }

#if 1

  if( p->pOrderBy ){
    return multiSelectOrderBy(pParse, p, pDest, aff);
  }
#endif

  /* Generate code for the left and right SELECT statements.
  */
  pOrderBy = p->pOrderBy;
  switch( p->op ){
    case TK_ALL: {
      if( pOrderBy==0 ){
        int addr = 0;
        assert( !pPrior->pLimit );
        pPrior->pLimit = p->pLimit;
        pPrior->pOffset = p->pOffset;
        rc = sqlite3Select(pParse, pPrior, &dest, 0, 0, 0, aff);
        p->pLimit = 0;
        p->pOffset = 0;
        if( rc ){
          goto multi_select_end;
        }
        p->pPrior = 0;
        p->iLimit = pPrior->iLimit;
        p->iOffset = pPrior->iOffset;
        if( p->iLimit ){
          addr = sqlite3VdbeAddOp1(v, OP_IfZero, p->iLimit);
          VdbeComment((v, "Jump ahead if LIMIT reached"));
        }
        rc = sqlite3Select(pParse, p, &dest, 0, 0, 0, aff);
        pDelete = p->pPrior;
        p->pPrior = pPrior;
        if( rc ){
          goto multi_select_end;
        }
        if( addr ){
          sqlite3VdbeJumpHere(v, addr);
        }
        break;
      }
      /* For UNION ALL ... ORDER BY fall through to the next case */
    }
    case TK_EXCEPT:
    case TK_UNION: {
      int unionTab;    /* Cursor number of the temporary table holding result */
      int op = 0;      /* One of the SRT_ operations to apply to self */
      int priorOp;     /* The SRT_ operation to apply to prior selects */
      Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
      int addr;
      SelectDest uniondest;

      priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
      if( dest.eDest==priorOp && pOrderBy==0 && !p->pLimit && !p->pOffset ){
        /* We can reuse a temporary table generated by a SELECT to our
        ** right.
        */
        unionTab = dest.iParm;
      }else{
        /* We will need to create our own temporary table to hold the
        ** intermediate results.
................................................................................
          assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
          aSetP2[nSetP2++] = addr;
        }else{
          assert( p->addrOpenEphm[0] == -1 );
          p->addrOpenEphm[0] = addr;
          p->pRightmost->usesEphm = 1;
        }
        createSortingIndex(pParse, p, pOrderBy);
        assert( p->pEList );
      }

      /* Code the SELECT statements to our left
      */
      assert( !pPrior->pOrderBy );
      sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
      rc = sqlite3Select(pParse, pPrior, &uniondest, 0, 0, 0, aff);
      if( rc ){
        goto multi_select_end;
      }

      /* Code the current SELECT statement
      */
      switch( p->op ){
         case TK_EXCEPT:  op = SRT_Except;   break;
         case TK_UNION:   op = SRT_Union;    break;
         case TK_ALL:     op = SRT_Table;    break;
      }
      p->pPrior = 0;
      p->pOrderBy = 0;
      p->disallowOrderBy = pOrderBy!=0;
      pLimit = p->pLimit;
      p->pLimit = 0;
      pOffset = p->pOffset;
      p->pOffset = 0;
      uniondest.eDest = op;
      rc = sqlite3Select(pParse, p, &uniondest, 0, 0, 0, aff);
      /* Query flattening in sqlite3Select() might refill p->pOrderBy.
      ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
      sqlite3ExprListDelete(p->pOrderBy);
      pDelete = p->pPrior;
      p->pPrior = pPrior;
      p->pOrderBy = pOrderBy;
      sqlite3ExprDelete(p->pLimit);
      p->pLimit = pLimit;
      p->pOffset = pOffset;
      p->iLimit = 0;
      p->iOffset = 0;
      if( rc ){
        goto multi_select_end;
................................................................................
        }
        iBreak = sqlite3VdbeMakeLabel(v);
        iCont = sqlite3VdbeMakeLabel(v);
        computeLimitRegisters(pParse, p, iBreak);
        sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak);
        iStart = sqlite3VdbeCurrentAddr(v);
        selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
                        pOrderBy, -1, &dest, iCont, iBreak, 0);
        sqlite3VdbeResolveLabel(v, iCont);
        sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart);
        sqlite3VdbeResolveLabel(v, iBreak);
        sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0);
      }
      break;
    }
................................................................................
      */
      tab1 = pParse->nTab++;
      tab2 = pParse->nTab++;
      if( processCompoundOrderBy(pParse, p, tab1) ){
        rc = 1;
        goto multi_select_end;
      }
      createSortingIndex(pParse, p, pOrderBy);

      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
      assert( p->addrOpenEphm[0] == -1 );
      p->addrOpenEphm[0] = addr;
      p->pRightmost->usesEphm = 1;
      assert( p->pEList );

      /* Code the SELECTs to our left into temporary table "tab1".
      */
      sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
      rc = sqlite3Select(pParse, pPrior, &intersectdest, 0, 0, 0, aff);
      if( rc ){
        goto multi_select_end;
      }

      /* Code the current SELECT into temporary table "tab2"
      */
      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0);
................................................................................
      p->addrOpenEphm[1] = addr;
      p->pPrior = 0;
      pLimit = p->pLimit;
      p->pLimit = 0;
      pOffset = p->pOffset;
      p->pOffset = 0;
      intersectdest.iParm = tab2;
      rc = sqlite3Select(pParse, p, &intersectdest, 0, 0, 0, aff);
      pDelete = p->pPrior;
      p->pPrior = pPrior;
      sqlite3ExprDelete(p->pLimit);
      p->pLimit = pLimit;
      p->pOffset = pOffset;
      if( rc ){
        goto multi_select_end;
................................................................................
      computeLimitRegisters(pParse, p, iBreak);
      sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak);
      r1 = sqlite3GetTempReg(pParse);
      iStart = sqlite3VdbeAddOp2(v, OP_RowKey, tab1, r1);
      sqlite3VdbeAddOp3(v, OP_NotFound, tab2, iCont, r1);
      sqlite3ReleaseTempReg(pParse, r1);
      selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
                      pOrderBy, -1, &dest, iCont, iBreak, 0);
      sqlite3VdbeResolveLabel(v, iCont);
      sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart);
      sqlite3VdbeResolveLabel(v, iBreak);
      sqlite3VdbeAddOp2(v, OP_Close, tab2, 0);
      sqlite3VdbeAddOp2(v, OP_Close, tab1, 0);
      break;
    }
................................................................................
  /* Set the number of columns in temporary tables
  */
  nCol = p->pEList->nExpr;
  while( nSetP2 ){
    sqlite3VdbeChangeP2(v, aSetP2[--nSetP2], nCol);
  }

  /* Compute collating sequences used by either the ORDER BY clause or
  ** by any temporary tables needed to implement the compound select.
  ** Attach the KeyInfo structure to all temporary tables.  Invoke the
  ** ORDER BY processing if there is an ORDER BY clause.
  **
  ** This section is run by the right-most SELECT statement only.
  ** SELECT statements to the left always skip this part.  The right-most
  ** SELECT might also skip this part if it has no ORDER BY clause and
  ** no temp tables are required.
  */
  if( pOrderBy || p->usesEphm ){
    int i;                        /* Loop counter */
    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
    Select *pLoop;                /* For looping through SELECT statements */
    int nKeyCol;                  /* Number of entries in pKeyInfo->aCol[] */
    CollSeq **apColl;             /* For looping through pKeyInfo->aColl[] */
    CollSeq **aCopy;              /* A copy of pKeyInfo->aColl[] */

    assert( p->pRightmost==p );
    nKeyCol = nCol + (pOrderBy ? pOrderBy->nExpr : 0);
    pKeyInfo = sqlite3DbMallocZero(pParse->db,
                       sizeof(*pKeyInfo)+nKeyCol*(sizeof(CollSeq*) + 1));
    if( !pKeyInfo ){
      rc = SQLITE_NOMEM;
      goto multi_select_end;
    }

    pKeyInfo->enc = ENC(pParse->db);
    pKeyInfo->nField = nCol;
................................................................................
          break;
        }
        sqlite3VdbeChangeP2(v, addr, nCol);
        sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO);
        pLoop->addrOpenEphm[i] = -1;
      }
    }

    if( pOrderBy ){
      struct ExprList_item *pOTerm = pOrderBy->a;
      int nOrderByExpr = pOrderBy->nExpr;
      int addr;
      u8 *pSortOrder;

      /* Reuse the same pKeyInfo for the ORDER BY as was used above for
      ** the compound select statements.  Except we have to change out the
      ** pKeyInfo->aColl[] values.  Some of the aColl[] values will be
      ** reused when constructing the pKeyInfo for the ORDER BY, so make
      ** a copy.  Sufficient space to hold both the nCol entries for
      ** the compound select and the nOrderbyExpr entries for the ORDER BY
      ** was allocated above.  But we need to move the compound select
      ** entries out of the way before constructing the ORDER BY entries.
      ** Move the compound select entries into aCopy[] where they can be
      ** accessed and reused when constructing the ORDER BY entries.
      ** Because nCol might be greater than or less than nOrderByExpr
      ** we have to use memmove() when doing the copy.
      */
      aCopy = &pKeyInfo->aColl[nOrderByExpr];
      pSortOrder = pKeyInfo->aSortOrder = (u8*)&aCopy[nCol];
      memmove(aCopy, pKeyInfo->aColl, nCol*sizeof(CollSeq*));

      apColl = pKeyInfo->aColl;
      for(i=0; i<nOrderByExpr; i++, pOTerm++, apColl++, pSortOrder++){
        Expr *pExpr = pOTerm->pExpr;
        if( (pExpr->flags & EP_ExpCollate) ){
          assert( pExpr->pColl!=0 );
          *apColl = pExpr->pColl;
        }else{
          *apColl = aCopy[pExpr->iColumn];
        }
        *pSortOrder = pOTerm->sortOrder;
      }
      assert( p->pRightmost==p );
      assert( p->addrOpenEphm[2]>=0 );
      addr = p->addrOpenEphm[2];
      sqlite3VdbeChangeP2(v, addr, p->pOrderBy->nExpr+2);
      pKeyInfo->nField = nOrderByExpr;
      sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO_HANDOFF);
      pKeyInfo = 0;
      generateSortTail(pParse, p, v, p->pEList->nExpr, &dest);
    }

    sqlite3_free(pKeyInfo);
  }

multi_select_end:
  pDest->iMem = dest.iMem;
  pDest->nMem = dest.nMem;
  sqlite3SelectDelete(pDelete);
................................................................................
** actually called using Gosub and they do not Return.  EofA and EofB loop
** until all data is exhausted then jump to the "end" labe.  AltB, AeqB,
** and AgtB jump to either L2 or to one of EofA or EofB.
*/
static int multiSelectOrderBy(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The right-most of SELECTs to be coded */
  SelectDest *pDest,    /* What to do with query results */
  char *aff             /* If eDest is SRT_Union, the affinity string */
){
  int i, j;             /* Loop counters */
  Select *pPrior;       /* Another SELECT immediately to our left */
  Vdbe *v;              /* Generate code to this VDBE */
  SelectDest destA;     /* Destination for coroutine A */
  SelectDest destB;     /* Destination for coroutine B */
  int regAddrA;         /* Address register for select-A coroutine */
................................................................................


  /* Generate a coroutine to evaluate the SELECT statement to the
  ** left of the compound operator - the "A" select.
  */
  VdbeNoopComment((v, "Begin coroutine for left SELECT"));
  pPrior->iLimit = regLimitA;
  sqlite3Select(pParse, pPrior, &destA, 0, 0, 0, 0);
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
  VdbeNoopComment((v, "End coroutine for left SELECT"));

  /* Generate a coroutine to evaluate the SELECT statement on 
  ** the right - the "B" select
  */
  addrSelectB = sqlite3VdbeCurrentAddr(v);
  VdbeNoopComment((v, "Begin coroutine for right SELECT"));
  savedLimit = p->iLimit;
  savedOffset = p->iOffset;
  p->iLimit = regLimitB;
  p->iOffset = 0;  
  sqlite3Select(pParse, p, &destB, 0, 0, 0, 0);
  p->iLimit = savedLimit;
  p->iOffset = savedOffset;
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
  VdbeNoopComment((v, "End coroutine for right SELECT"));

  /* Generate a subroutine that outputs the current row of the A
................................................................................
*/
int sqlite3Select(
  Parse *pParse,         /* The parser context */
  Select *p,             /* The SELECT statement being coded. */
  SelectDest *pDest,     /* What to do with the query results */
  Select *pParent,       /* Another SELECT for which this is a sub-query */
  int parentTab,         /* Index in pParent->pSrc of this query */
  int *pParentAgg,       /* True if pParent uses aggregate functions */
  char *aff              /* If eDest is SRT_Union, the affinity string */
){
  int i, j;              /* Loop counters */
  WhereInfo *pWInfo;     /* Return from sqlite3WhereBegin() */
  Vdbe *v;               /* The virtual machine under construction */
  int isAgg;             /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of columns to extract. */
  SrcList *pTabList;     /* List of tables to select from */
................................................................................
    if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
      if( isAggSub ){
        p->isAgg = isAgg = 1;
      }
      i = -1;
    }else{
      sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
      sqlite3Select(pParse, pSub, &dest, p, i, &isAgg, 0);
    }
    if( pParse->nErr || db->mallocFailed ){
      goto select_end;
    }
    pParse->nHeight -= sqlite3SelectExprHeight(p);
    pTabList = p->pSrc;
    if( !IgnorableOrderby(pDest) ){
................................................................................
      }
      mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
      if( mxSelect && cnt>mxSelect ){
        sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
        return 1;
      }
    }
    return multiSelect(pParse, p, pDest, aff);
  }
#endif

  /* If writing to memory or generating a set
  ** only a single column may be output.
  */
#ifndef SQLITE_OMIT_SUBQUERY
................................................................................
      p->addrOpenEphm[2] = -1;
    }

    /* Use the standard inner loop
    */
    assert(!isDistinct);
    selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, -1, pDest,
                    pWInfo->iContinue, pWInfo->iBreak, aff);

    /* End the database scan loop.
    */
    sqlite3WhereEnd(pWInfo);
  }else{
    /* This is the processing for aggregate queries */
    NameContext sNC;    /* Name context for processing aggregate information */
................................................................................
      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
      finalizeAggFunctions(pParse, &sAggInfo);
      if( pHaving ){
        sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
      }
      selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
                      distinct, pDest,
                      addrOutputRow+1, addrSetAbort, aff);
      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
      VdbeComment((v, "end groupby result generator"));

      /* Generate a subroutine that will reset the group-by accumulator
      */
      addrReset = sqlite3VdbeCurrentAddr(v);
      regReset = ++pParse->nMem;
................................................................................
      sqlite3WhereEnd(pWInfo);
      finalizeAggFunctions(pParse, &sAggInfo);
      pOrderBy = 0;
      if( pHaving ){
        sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
      }
      selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1, 
                      pDest, addrEnd, addrEnd, aff);

      sqlite3ExprListDelete(pDel);
    }
    sqlite3VdbeResolveLabel(v, addrEnd);
    
  } /* endif aggregate query */

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.451 2008/07/08 23:40:20 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
................................................................................
      break;
    }
  }
  if(
     (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
     (jointype & JT_ERROR)!=0
  ){
    const char *zSp = " ";
    assert( pB!=0 );

    if( pC==0 ){ zSp++; }
    sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "

       "%T %T%s%T", pA, pB, zSp, pC);
    jointype = JT_INNER;
  }else if( jointype & JT_RIGHT ){
    sqlite3ErrorMsg(pParse, 
      "RIGHT and FULL OUTER JOINs are not currently supported");
    jointype = JT_INNER;
  }
  return jointype;
................................................................................
  ExprList *pEList,       /* List of values being extracted */
  int srcTab,             /* Pull data from this table */
  int nColumn,            /* Number of columns in the source table */
  ExprList *pOrderBy,     /* If not NULL, sort results using this key */
  int distinct,           /* If >=0, make sure results are distinct */
  SelectDest *pDest,      /* How to dispose of the results */
  int iContinue,          /* Jump here to continue with next row */
  int iBreak              /* Jump here to break out of the inner loop */

){
  Vdbe *v = pParse->pVdbe;
  int i;
  int hasDistinct;        /* True if the DISTINCT keyword is present */
  int regResult;              /* Start of memory holding result set */
  int eDest = pDest->eDest;   /* How to dispose of results */
  int iParm = pDest->iParm;   /* First argument to disposal method */
................................................................................
    ** table iParm.
    */
#ifndef SQLITE_OMIT_COMPOUND_SELECT
    case SRT_Union: {
      int r1;
      r1 = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);



      sqlite3VdbeAddOp2(v, OP_IdxInsert, iParm, r1);
      sqlite3ReleaseTempReg(pParse, r1);
      break;
    }

    /* Construct a record from the query result, but instead of
    ** saving that record, use it as a key to delete elements from
................................................................................
      for(i=0; i<nColumn; i++){
        assert( regRow!=pDest->iMem+i );
        sqlite3VdbeAddOp3(v, OP_Column, pseudoTab, i, pDest->iMem+i);
      }
      if( eDest==SRT_Callback ){
        sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iMem, nColumn);
        sqlite3ExprCacheAffinityChange(pParse, pDest->iMem, nColumn);
      }else{
        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
      }
      break;
    }
    default: {
      /* Do nothing */
      break;
    }
  }
  sqlite3ReleaseTempReg(pParse, regRow);
  sqlite3ReleaseTempReg(pParse, regRowid);

  /* LIMIT has been implemented by the pushOntoSorter() routine.
  */
  assert( p->iLimit==0 );




  /* The bottom of the loop
  */
  sqlite3VdbeResolveLabel(v, cont);
  sqlite3VdbeAddOp2(v, OP_Next, iTab, addr);
  sqlite3VdbeResolveLabel(v, brk);
  if( eDest==SRT_Callback || eDest==SRT_Coroutine ){
................................................................................
      addr1 = sqlite3VdbeAddOp1(v, OP_IfPos, iLimit);
      sqlite3VdbeAddOp2(v, OP_Integer, -1, iOffset+1);
      sqlite3VdbeJumpHere(v, addr1);
    }
  }
}
















#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** Return the appropriate collating sequence for the iCol-th column of
** the result set for the compound-select statement "p".  Return NULL if
** the column has no default collating sequence.
**
** The collating sequence for the compound select is taken from the
................................................................................
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */

/* Forward reference */
static int multiSelectOrderBy(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The right-most of SELECTs to be coded */
  SelectDest *pDest     /* What to do with query results */

);


#ifndef SQLITE_OMIT_COMPOUND_SELECT
/*
** This routine is called to process a compound query form from
** two or more separate queries using UNION, UNION ALL, EXCEPT, or
................................................................................
**
** Notice that because of the way SQLite parses compound SELECTs, the
** individual selects always group from left to right.
*/
static int multiSelect(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The right-most of SELECTs to be coded */
  SelectDest *pDest     /* What to do with query results */

){
  int rc = SQLITE_OK;   /* Success code from a subroutine */
  Select *pPrior;       /* Another SELECT immediately to our left */
  Vdbe *v;              /* Generate code to this VDBE */
  int nCol;             /* Number of columns in the result set */

  int aSetP2[2];        /* Set P2 value of these op to number of columns */
  int nSetP2 = 0;       /* Number of slots in aSetP2[] used */
  SelectDest dest;      /* Alternative data destination */
  Select *pDelete = 0;  /* Chain of simple selects to delete */

  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
................................................................................
  if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
    sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
      " do not have the same number of result columns", selectOpName(p->op));
    rc = 1;
    goto multi_select_end;
  }

  /* Compound SELECTs that have an ORDER BY clause are handled separately.
  */
  if( p->pOrderBy ){
    return multiSelectOrderBy(pParse, p, pDest);
  }


  /* Generate code for the left and right SELECT statements.
  */

  switch( p->op ){
    case TK_ALL: {

      int addr = 0;
      assert( !pPrior->pLimit );
      pPrior->pLimit = p->pLimit;
      pPrior->pOffset = p->pOffset;
      rc = sqlite3Select(pParse, pPrior, &dest, 0, 0, 0);
      p->pLimit = 0;
      p->pOffset = 0;
      if( rc ){
        goto multi_select_end;
      }
      p->pPrior = 0;
      p->iLimit = pPrior->iLimit;
      p->iOffset = pPrior->iOffset;
      if( p->iLimit ){
        addr = sqlite3VdbeAddOp1(v, OP_IfZero, p->iLimit);
        VdbeComment((v, "Jump ahead if LIMIT reached"));
      }
      rc = sqlite3Select(pParse, p, &dest, 0, 0, 0);
      pDelete = p->pPrior;
      p->pPrior = pPrior;
      if( rc ){
        goto multi_select_end;
      }
      if( addr ){
        sqlite3VdbeJumpHere(v, addr);
      }
      break;


    }
    case TK_EXCEPT:
    case TK_UNION: {
      int unionTab;    /* Cursor number of the temporary table holding result */
      int op = 0;      /* One of the SRT_ operations to apply to self */
      int priorOp;     /* The SRT_ operation to apply to prior selects */
      Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
      int addr;
      SelectDest uniondest;

      priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
      if( dest.eDest==priorOp && !p->pLimit && !p->pOffset ){
        /* We can reuse a temporary table generated by a SELECT to our
        ** right.
        */
        unionTab = dest.iParm;
      }else{
        /* We will need to create our own temporary table to hold the
        ** intermediate results.
................................................................................
          assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
          aSetP2[nSetP2++] = addr;
        }else{
          assert( p->addrOpenEphm[0] == -1 );
          p->addrOpenEphm[0] = addr;
          p->pRightmost->usesEphm = 1;
        }

        assert( p->pEList );
      }

      /* Code the SELECT statements to our left
      */
      assert( !pPrior->pOrderBy );
      sqlite3SelectDestInit(&uniondest, priorOp, unionTab);
      rc = sqlite3Select(pParse, pPrior, &uniondest, 0, 0, 0);
      if( rc ){
        goto multi_select_end;
      }

      /* Code the current SELECT statement
      */
      switch( p->op ){
         case TK_EXCEPT:  op = SRT_Except;   break;
         case TK_UNION:   op = SRT_Union;    break;
         case TK_ALL:     op = SRT_Table;    break;
      }
      p->pPrior = 0;

      p->disallowOrderBy = 0;
      pLimit = p->pLimit;
      p->pLimit = 0;
      pOffset = p->pOffset;
      p->pOffset = 0;
      uniondest.eDest = op;
      rc = sqlite3Select(pParse, p, &uniondest, 0, 0, 0);
      /* Query flattening in sqlite3Select() might refill p->pOrderBy.
      ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
      sqlite3ExprListDelete(p->pOrderBy);
      pDelete = p->pPrior;
      p->pPrior = pPrior;
      p->pOrderBy = 0;
      sqlite3ExprDelete(p->pLimit);
      p->pLimit = pLimit;
      p->pOffset = pOffset;
      p->iLimit = 0;
      p->iOffset = 0;
      if( rc ){
        goto multi_select_end;
................................................................................
        }
        iBreak = sqlite3VdbeMakeLabel(v);
        iCont = sqlite3VdbeMakeLabel(v);
        computeLimitRegisters(pParse, p, iBreak);
        sqlite3VdbeAddOp2(v, OP_Rewind, unionTab, iBreak);
        iStart = sqlite3VdbeCurrentAddr(v);
        selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
                        0, -1, &dest, iCont, iBreak);
        sqlite3VdbeResolveLabel(v, iCont);
        sqlite3VdbeAddOp2(v, OP_Next, unionTab, iStart);
        sqlite3VdbeResolveLabel(v, iBreak);
        sqlite3VdbeAddOp2(v, OP_Close, unionTab, 0);
      }
      break;
    }
................................................................................
      */
      tab1 = pParse->nTab++;
      tab2 = pParse->nTab++;
      if( processCompoundOrderBy(pParse, p, tab1) ){
        rc = 1;
        goto multi_select_end;
      }


      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab1, 0);
      assert( p->addrOpenEphm[0] == -1 );
      p->addrOpenEphm[0] = addr;
      p->pRightmost->usesEphm = 1;
      assert( p->pEList );

      /* Code the SELECTs to our left into temporary table "tab1".
      */
      sqlite3SelectDestInit(&intersectdest, SRT_Union, tab1);
      rc = sqlite3Select(pParse, pPrior, &intersectdest, 0, 0, 0);
      if( rc ){
        goto multi_select_end;
      }

      /* Code the current SELECT into temporary table "tab2"
      */
      addr = sqlite3VdbeAddOp2(v, OP_OpenEphemeral, tab2, 0);
................................................................................
      p->addrOpenEphm[1] = addr;
      p->pPrior = 0;
      pLimit = p->pLimit;
      p->pLimit = 0;
      pOffset = p->pOffset;
      p->pOffset = 0;
      intersectdest.iParm = tab2;
      rc = sqlite3Select(pParse, p, &intersectdest, 0, 0, 0);
      pDelete = p->pPrior;
      p->pPrior = pPrior;
      sqlite3ExprDelete(p->pLimit);
      p->pLimit = pLimit;
      p->pOffset = pOffset;
      if( rc ){
        goto multi_select_end;
................................................................................
      computeLimitRegisters(pParse, p, iBreak);
      sqlite3VdbeAddOp2(v, OP_Rewind, tab1, iBreak);
      r1 = sqlite3GetTempReg(pParse);
      iStart = sqlite3VdbeAddOp2(v, OP_RowKey, tab1, r1);
      sqlite3VdbeAddOp3(v, OP_NotFound, tab2, iCont, r1);
      sqlite3ReleaseTempReg(pParse, r1);
      selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
                      0, -1, &dest, iCont, iBreak);
      sqlite3VdbeResolveLabel(v, iCont);
      sqlite3VdbeAddOp2(v, OP_Next, tab1, iStart);
      sqlite3VdbeResolveLabel(v, iBreak);
      sqlite3VdbeAddOp2(v, OP_Close, tab2, 0);
      sqlite3VdbeAddOp2(v, OP_Close, tab1, 0);
      break;
    }
................................................................................
  /* Set the number of columns in temporary tables
  */
  nCol = p->pEList->nExpr;
  while( nSetP2 ){
    sqlite3VdbeChangeP2(v, aSetP2[--nSetP2], nCol);
  }

  /* Compute collating sequences used by 
  ** temporary tables needed to implement the compound select.
  ** Attach the KeyInfo structure to all temporary tables.

  **
  ** This section is run by the right-most SELECT statement only.
  ** SELECT statements to the left always skip this part.  The right-most
  ** SELECT might also skip this part if it has no ORDER BY clause and
  ** no temp tables are required.
  */
  if( p->usesEphm ){
    int i;                        /* Loop counter */
    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
    Select *pLoop;                /* For looping through SELECT statements */

    CollSeq **apColl;             /* For looping through pKeyInfo->aColl[] */


    assert( p->pRightmost==p );

    pKeyInfo = sqlite3DbMallocZero(pParse->db,
                       sizeof(*pKeyInfo)+nCol*(sizeof(CollSeq*) + 1));
    if( !pKeyInfo ){
      rc = SQLITE_NOMEM;
      goto multi_select_end;
    }

    pKeyInfo->enc = ENC(pParse->db);
    pKeyInfo->nField = nCol;
................................................................................
          break;
        }
        sqlite3VdbeChangeP2(v, addr, nCol);
        sqlite3VdbeChangeP4(v, addr, (char*)pKeyInfo, P4_KEYINFO);
        pLoop->addrOpenEphm[i] = -1;
      }
    }













































    sqlite3_free(pKeyInfo);
  }

multi_select_end:
  pDest->iMem = dest.iMem;
  pDest->nMem = dest.nMem;
  sqlite3SelectDelete(pDelete);
................................................................................
** actually called using Gosub and they do not Return.  EofA and EofB loop
** until all data is exhausted then jump to the "end" labe.  AltB, AeqB,
** and AgtB jump to either L2 or to one of EofA or EofB.
*/
static int multiSelectOrderBy(
  Parse *pParse,        /* Parsing context */
  Select *p,            /* The right-most of SELECTs to be coded */
  SelectDest *pDest     /* What to do with query results */

){
  int i, j;             /* Loop counters */
  Select *pPrior;       /* Another SELECT immediately to our left */
  Vdbe *v;              /* Generate code to this VDBE */
  SelectDest destA;     /* Destination for coroutine A */
  SelectDest destB;     /* Destination for coroutine B */
  int regAddrA;         /* Address register for select-A coroutine */
................................................................................


  /* Generate a coroutine to evaluate the SELECT statement to the
  ** left of the compound operator - the "A" select.
  */
  VdbeNoopComment((v, "Begin coroutine for left SELECT"));
  pPrior->iLimit = regLimitA;
  sqlite3Select(pParse, pPrior, &destA, 0, 0, 0);
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofA);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
  VdbeNoopComment((v, "End coroutine for left SELECT"));

  /* Generate a coroutine to evaluate the SELECT statement on 
  ** the right - the "B" select
  */
  addrSelectB = sqlite3VdbeCurrentAddr(v);
  VdbeNoopComment((v, "Begin coroutine for right SELECT"));
  savedLimit = p->iLimit;
  savedOffset = p->iOffset;
  p->iLimit = regLimitB;
  p->iOffset = 0;  
  sqlite3Select(pParse, p, &destB, 0, 0, 0);
  p->iLimit = savedLimit;
  p->iOffset = savedOffset;
  sqlite3VdbeAddOp2(v, OP_Integer, 1, regEofB);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
  VdbeNoopComment((v, "End coroutine for right SELECT"));

  /* Generate a subroutine that outputs the current row of the A
................................................................................
*/
int sqlite3Select(
  Parse *pParse,         /* The parser context */
  Select *p,             /* The SELECT statement being coded. */
  SelectDest *pDest,     /* What to do with the query results */
  Select *pParent,       /* Another SELECT for which this is a sub-query */
  int parentTab,         /* Index in pParent->pSrc of this query */
  int *pParentAgg        /* True if pParent uses aggregate functions */

){
  int i, j;              /* Loop counters */
  WhereInfo *pWInfo;     /* Return from sqlite3WhereBegin() */
  Vdbe *v;               /* The virtual machine under construction */
  int isAgg;             /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of columns to extract. */
  SrcList *pTabList;     /* List of tables to select from */
................................................................................
    if( flattenSubquery(pParse, p, i, isAgg, isAggSub) ){
      if( isAggSub ){
        p->isAgg = isAgg = 1;
      }
      i = -1;
    }else{
      sqlite3SelectDestInit(&dest, SRT_EphemTab, pItem->iCursor);
      sqlite3Select(pParse, pSub, &dest, p, i, &isAgg);
    }
    if( pParse->nErr || db->mallocFailed ){
      goto select_end;
    }
    pParse->nHeight -= sqlite3SelectExprHeight(p);
    pTabList = p->pSrc;
    if( !IgnorableOrderby(pDest) ){
................................................................................
      }
      mxSelect = db->aLimit[SQLITE_LIMIT_COMPOUND_SELECT];
      if( mxSelect && cnt>mxSelect ){
        sqlite3ErrorMsg(pParse, "too many terms in compound SELECT");
        return 1;
      }
    }
    return multiSelect(pParse, p, pDest);
  }
#endif

  /* If writing to memory or generating a set
  ** only a single column may be output.
  */
#ifndef SQLITE_OMIT_SUBQUERY
................................................................................
      p->addrOpenEphm[2] = -1;
    }

    /* Use the standard inner loop
    */
    assert(!isDistinct);
    selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, -1, pDest,
                    pWInfo->iContinue, pWInfo->iBreak);

    /* End the database scan loop.
    */
    sqlite3WhereEnd(pWInfo);
  }else{
    /* This is the processing for aggregate queries */
    NameContext sNC;    /* Name context for processing aggregate information */
................................................................................
      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
      finalizeAggFunctions(pParse, &sAggInfo);
      if( pHaving ){
        sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, SQLITE_JUMPIFNULL);
      }
      selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
                      distinct, pDest,
                      addrOutputRow+1, addrSetAbort);
      sqlite3VdbeAddOp1(v, OP_Return, regOutputRow);
      VdbeComment((v, "end groupby result generator"));

      /* Generate a subroutine that will reset the group-by accumulator
      */
      addrReset = sqlite3VdbeCurrentAddr(v);
      regReset = ++pParse->nMem;
................................................................................
      sqlite3WhereEnd(pWInfo);
      finalizeAggFunctions(pParse, &sAggInfo);
      pOrderBy = 0;
      if( pHaving ){
        sqlite3ExprIfFalse(pParse, pHaving, addrEnd, SQLITE_JUMPIFNULL);
      }
      selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1, 
                      pDest, addrEnd, addrEnd);

      sqlite3ExprListDelete(pDel);
    }
    sqlite3VdbeResolveLabel(v, addrEnd);
    
  } /* endif aggregate query */

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.737 2008/07/08 22:28:49 shane Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build
................................................................................
void sqlite3SrcListShiftJoinType(SrcList*);
void sqlite3SrcListAssignCursors(Parse*, SrcList*);
void sqlite3IdListDelete(IdList*);
void sqlite3SrcListDelete(SrcList*);
void sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
                        Token*, int, int);
void sqlite3DropIndex(Parse*, SrcList*, int);
int sqlite3Select(Parse*, Select*, SelectDest*, Select*, int, int*, char *aff);
Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
                         Expr*,ExprList*,int,Expr*,Expr*);
void sqlite3SelectDelete(Select*);
Table *sqlite3SrcListLookup(Parse*, SrcList*);
int sqlite3IsReadOnly(Parse*, Table*, int);
void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.738 2008/07/08 23:40:20 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build
................................................................................
void sqlite3SrcListShiftJoinType(SrcList*);
void sqlite3SrcListAssignCursors(Parse*, SrcList*);
void sqlite3IdListDelete(IdList*);
void sqlite3SrcListDelete(SrcList*);
void sqlite3CreateIndex(Parse*,Token*,Token*,SrcList*,ExprList*,int,Token*,
                        Token*, int, int);
void sqlite3DropIndex(Parse*, SrcList*, int);
int sqlite3Select(Parse*, Select*, SelectDest*, Select*, int, int*);
Select *sqlite3SelectNew(Parse*,ExprList*,SrcList*,Expr*,ExprList*,
                         Expr*,ExprList*,int,Expr*,Expr*);
void sqlite3SelectDelete(Select*);
Table *sqlite3SrcListLookup(Parse*, SrcList*);
int sqlite3IsReadOnly(Parse*, Table*, int);
void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);

** 
** This file contains code used for testing the SQLite system.
** None of the code in this file goes into a deliverable build.
** 
** The focus of this file is providing the TCL testing layer
** access to compile-time constants.
**
** $Id: test_config.c,v 1.30 2008/06/26 10:54:12 danielk1977 Exp $
*/

#include "sqliteLimit.h"

#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
................................................................................

#ifdef SQLITE_DISABLE_LFS
  Tcl_SetVar2(interp, "sqlite_options", "lfs", "0", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "lfs", "1", TCL_GLOBAL_ONLY);
#endif

#ifdef SQLITE_MEMDEBUG
  Tcl_SetVar2(interp, "sqlite_options", "memdebug", "1", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "memdebug", "0", TCL_GLOBAL_ONLY);
#endif

#ifdef SQLITE_ENABLE_MEMSYS3
  Tcl_SetVar2(interp, "sqlite_options", "mem3", "1", TCL_GLOBAL_ONLY);

** 
** This file contains code used for testing the SQLite system.
** None of the code in this file goes into a deliverable build.
** 
** The focus of this file is providing the TCL testing layer
** access to compile-time constants.
**
** $Id: test_config.c,v 1.31 2008/07/08 23:40:20 drh Exp $
*/

#include "sqliteLimit.h"

#include "sqliteInt.h"
#include "tcl.h"
#include <stdlib.h>
................................................................................

#ifdef SQLITE_DISABLE_LFS
  Tcl_SetVar2(interp, "sqlite_options", "lfs", "0", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "lfs", "1", TCL_GLOBAL_ONLY);
#endif

#if 1 /* def SQLITE_MEMDEBUG */
  Tcl_SetVar2(interp, "sqlite_options", "memdebug", "1", TCL_GLOBAL_ONLY);
#else
  Tcl_SetVar2(interp, "sqlite_options", "memdebug", "0", TCL_GLOBAL_ONLY);
#endif

#ifdef SQLITE_ENABLE_MEMSYS3
  Tcl_SetVar2(interp, "sqlite_options", "mem3", "1", TCL_GLOBAL_ONLY);

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
**
** $Id: trigger.c,v 1.126 2008/05/16 04:51:55 danielk1977 Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_TRIGGER
/*
** Delete a linked list of TriggerStep structures.
*/
................................................................................
      case TK_SELECT: {
        Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect);
        if( ss ){
          SelectDest dest;

          sqlite3SelectDestInit(&dest, SRT_Discard, 0);
          sqlite3SelectResolve(pParse, ss, 0);
          sqlite3Select(pParse, ss, &dest, 0, 0, 0, 0);
          sqlite3SelectDelete(ss);
        }
        break;
      }
      case TK_UPDATE: {
        SrcList *pSrc;
        pSrc = targetSrcList(pParse, pTriggerStep);

**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
**
** $Id: trigger.c,v 1.127 2008/07/08 23:40:20 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_TRIGGER
/*
** Delete a linked list of TriggerStep structures.
*/
................................................................................
      case TK_SELECT: {
        Select *ss = sqlite3SelectDup(db, pTriggerStep->pSelect);
        if( ss ){
          SelectDest dest;

          sqlite3SelectDestInit(&dest, SRT_Discard, 0);
          sqlite3SelectResolve(pParse, ss, 0);
          sqlite3Select(pParse, ss, &dest, 0, 0, 0);
          sqlite3SelectDelete(ss);
        }
        break;
      }
      case TK_UPDATE: {
        SrcList *pSrc;
        pSrc = targetSrcList(pParse, pTriggerStep);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.178 2008/04/28 18:46:43 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Forward declaration */
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */
................................................................................
  assert( v );
  ephemTab = pParse->nTab++;
  sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));

  /* fill the ephemeral table 
  */
  sqlite3SelectDestInit(&dest, SRT_Table, ephemTab);
  sqlite3Select(pParse, pSelect, &dest, 0, 0, 0, 0);

  /* Generate code to scan the ephemeral table and call VUpdate. */
  iReg = ++pParse->nMem;
  pParse->nMem += pTab->nCol+1;
  sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
  addr = sqlite3VdbeCurrentAddr(v);
  sqlite3VdbeAddOp3(v, OP_Column,  ephemTab, 0, iReg);

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle UPDATE statements.
**
** $Id: update.c,v 1.179 2008/07/08 23:40:20 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Forward declaration */
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */
................................................................................
  assert( v );
  ephemTab = pParse->nTab++;
  sqlite3VdbeAddOp2(v, OP_OpenEphemeral, ephemTab, pTab->nCol+1+(pRowid!=0));

  /* fill the ephemeral table 
  */
  sqlite3SelectDestInit(&dest, SRT_Table, ephemTab);
  sqlite3Select(pParse, pSelect, &dest, 0, 0, 0);

  /* Generate code to scan the ephemeral table and call VUpdate. */
  iReg = ++pParse->nMem;
  pParse->nMem += pTab->nCol+1;
  sqlite3VdbeAddOp2(v, OP_Rewind, ephemTab, 0);
  addr = sqlite3VdbeCurrentAddr(v);
  sqlite3VdbeAddOp3(v, OP_Column,  ephemTab, 0, iReg);

#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests for joins, including outer joins.
#
# $Id: join.test,v 1.22 2006/06/20 11:01:09 danielk1977 Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

do_test join-1.1 {
  execsql {
    CREATE TABLE t1(a,b,c);
................................................................................
  }
} {1 {a NATURAL join may not have an ON or USING clause}}
do_test join-3.3 {
  catchsql {
    SELECT * FROM t1 JOIN t2 ON t1.a=t2.b USING(b);
  }
} {1 {cannot have both ON and USING clauses in the same join}}
do_test join-3.4 {
  catchsql {
    SELECT * FROM t1 JOIN t2 USING(a);
  }
} {1 {cannot join using column a - column not present in both tables}}





do_test join-3.5 {
  catchsql {
    SELECT * FROM t1 USING(a);
  }
} {0 {1 2 3 2 3 4 3 4 5}}
do_test join-3.6 {
  catchsql {
................................................................................
  }
} {1 {no such column: t3.a}}
do_test join-3.7 {
  catchsql {
    SELECT * FROM t1 INNER OUTER JOIN t2;
  }
} {1 {unknown or unsupported join type: INNER OUTER}}
do_test join-3.7 {










  catchsql {
    SELECT * FROM t1 LEFT BOGUS JOIN t2;
  }
} {1 {unknown or unsupported join type: LEFT BOGUS}}











do_test join-4.1 {
  execsql {
    BEGIN;
    CREATE TABLE t5(a INTEGER PRIMARY KEY);
    CREATE TABLE t6(a INTEGER);
    INSERT INTO t6 VALUES(NULL);

#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
#
# This file implements tests for joins, including outer joins.
#
# $Id: join.test,v 1.23 2008/07/08 23:40:20 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

do_test join-1.1 {
  execsql {
    CREATE TABLE t1(a,b,c);
................................................................................
  }
} {1 {a NATURAL join may not have an ON or USING clause}}
do_test join-3.3 {
  catchsql {
    SELECT * FROM t1 JOIN t2 ON t1.a=t2.b USING(b);
  }
} {1 {cannot have both ON and USING clauses in the same join}}
do_test join-3.4.1 {
  catchsql {
    SELECT * FROM t1 JOIN t2 USING(a);
  }
} {1 {cannot join using column a - column not present in both tables}}
do_test join-3.4.2 {
  catchsql {
    SELECT * FROM t1 JOIN t2 USING(d);
  }
} {1 {cannot join using column d - column not present in both tables}}
do_test join-3.5 {
  catchsql {
    SELECT * FROM t1 USING(a);
  }
} {0 {1 2 3 2 3 4 3 4 5}}
do_test join-3.6 {
  catchsql {
................................................................................
  }
} {1 {no such column: t3.a}}
do_test join-3.7 {
  catchsql {
    SELECT * FROM t1 INNER OUTER JOIN t2;
  }
} {1 {unknown or unsupported join type: INNER OUTER}}
do_test join-3.8 {
  catchsql {
    SELECT * FROM t1 INNER OUTER CROSS JOIN t2;
  }
} {1 {unknown or unsupported join type: INNER OUTER CROSS}}
do_test join-3.9 {
  catchsql {
    SELECT * FROM t1 OUTER NATURAL INNER JOIN t2;
  }
} {1 {unknown or unsupported join type: OUTER NATURAL INNER}}
do_test join-3.10 {
  catchsql {
    SELECT * FROM t1 LEFT BOGUS JOIN t2;
  }
} {1 {unknown or unsupported join type: LEFT BOGUS}}
do_test join-3.11 {
  catchsql {
    SELECT * FROM t1 INNER BOGUS CROSS JOIN t2;
  }
} {1 {unknown or unsupported join type: INNER BOGUS CROSS}}
do_test join-3.12 {
  catchsql {
    SELECT * FROM t1 NATURAL AWK SED JOIN t2;
  }
} {1 {unknown or unsupported join type: NATURAL AWK SED}}

do_test join-4.1 {
  execsql {
    BEGIN;
    CREATE TABLE t5(a INTEGER PRIMARY KEY);
    CREATE TABLE t6(a INTEGER);
    INSERT INTO t6 VALUES(NULL);