SQLite

**    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 1.375 2008/06/24 00:32:35 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**

  pNew->pGroupBy = sqlite3ExprListDup(db, p->pGroupBy);
  pNew->pHaving = sqlite3ExprDup(db, p->pHaving);
  pNew->pOrderBy = sqlite3ExprListDup(db, p->pOrderBy);
  pNew->op = p->op;
  pNew->pPrior = sqlite3SelectDup(db, p->pPrior);
  pNew->pLimit = sqlite3ExprDup(db, p->pLimit);
  pNew->pOffset = sqlite3ExprDup(db, p->pOffset);
  pNew->iLimit = 0;
  pNew->iOffset = 0;
  pNew->isResolved = p->isResolved;
  pNew->isAgg = p->isAgg;
  pNew->usesEphm = 0;
  pNew->disallowOrderBy = 0;
  pNew->pRightmost = 0;
  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;

/*
** If the expression p codes a constant integer that is small enough
** to fit in a 32-bit integer, return 1 and put the value of the integer
** in *pValue.  If the expression is not an integer or if it is too big
** to fit in a signed 32-bit integer, return 0 and leave *pValue unchanged.
*/
int sqlite3ExprIsInteger(Expr *p, int *pValue){
  int rc = 0;
  if( p->flags & EP_IntValue ){
    *pValue = p->iTable;
    return 1;
  }
  switch( p->op ){
    case TK_INTEGER: {
      rc = sqlite3GetInt32((char*)p->token.z, pValue);


      break;
    }
    case TK_UPLUS: {
      rc = sqlite3ExprIsInteger(p->pLeft, pValue);
    }
    case TK_UMINUS: {
      int v;
      if( sqlite3ExprIsInteger(p->pLeft, &v) ){
        *pValue = -v;
        rc = 1;
      }
      break;
    }
    default: break;
  }
  if( rc ){
    p->op = TK_INTEGER;
    p->flags |= EP_IntValue;
    p->iTable = *pValue;
  }
  return rc;
}

/*
** Return TRUE if the given string is a row-id column name.
*/
int sqlite3IsRowid(const char *z){
  if( sqlite3StrICmp(z, "_ROWID_")==0 ) return 1;

** Generate an instruction that will put the integer describe by
** text z[0..n-1] into register iMem.
**
** The z[] string will probably not be zero-terminated.  But the 
** z[n] character is guaranteed to be something that does not look
** like the continuation of the number.
*/
static void codeInteger(Vdbe *v, Expr *pExpr, int negFlag, int iMem){
  const char *z;
  if( pExpr->flags & EP_IntValue ){
    int i = pExpr->iTable;
    if( negFlag ) i = -i;
    sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
  }else if( (z = (char*)pExpr->token.z)!=0 ){
    int i;
    int n = pExpr->token.n;
    assert( !isdigit(z[n]) );
    if( sqlite3GetInt32(z, &i) ){
      if( negFlag ) i = -i;
      sqlite3VdbeAddOp2(v, OP_Integer, i, iMem);
    }else if( sqlite3FitsIn64Bits(z, negFlag) ){
      i64 value;
      char *zV;

  for(i=0; i<pParse->nColCache; i++){
    int x = pParse->aColCache[i].iReg;
    if( x>=iFrom && x<iFrom+nReg ){
      pParse->aColCache[i].iReg += iTo-iFrom;
    }
  }
}

/*
** Generate code to copy content from registers iFrom...iFrom+nReg-1
** over to iTo..iTo+nReg-1.
*/
void sqlite3ExprCodeCopy(Parse *pParse, int iFrom, int iTo, int nReg){
  int i;
  if( iFrom==iTo ) return;
  for(i=0; i<nReg; i++){
    sqlite3VdbeAddOp2(pParse->pVdbe, OP_Copy, iFrom+i, iTo+i);
  }
}

/*
** Return true if any register in the range iFrom..iTo (inclusive)
** is used as part of the column cache.
*/
static int usedAsColumnCache(Parse *pParse, int iFrom, int iTo){
  int i;

        inReg = sqlite3ExprCodeGetColumn(pParse, pExpr->pTab,
                                 pExpr->iColumn, pExpr->iTable, target,
                                 pExpr->flags & EP_AnyAff);
      }
      break;
    }
    case TK_INTEGER: {
      codeInteger(v, pExpr, 0, target);
      break;
    }
    case TK_FLOAT: {
      codeReal(v, (char*)pExpr->token.z, pExpr->token.n, 0, target);
      break;
    }
    case TK_STRING: {

      testcase( regFree2==0 );
      break;
    }
    case TK_UMINUS: {
      Expr *pLeft = pExpr->pLeft;
      assert( pLeft );
      if( pLeft->op==TK_FLOAT || pLeft->op==TK_INTEGER ){

        if( pLeft->op==TK_FLOAT ){
          codeReal(v, (char*)pLeft->token.z, pLeft->token.n, 1, target);
        }else{
          codeInteger(v, pLeft, 1, target);
        }
      }else{
        regFree1 = r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp2(v, OP_Integer, 0, r1);
        r2 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree2);
        sqlite3VdbeAddOp3(v, OP_Subtract, r2, r1, target);
        testcase( regFree2==0 );

**    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 1.242 2008/06/24 00:32:35 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:

    ** the SELECT completes, it sets the EOF flag stored in regEof.
    */
    int rc, j1;

    regEof = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Integer, 0, regEof);      /* EOF <- 0 */
    VdbeComment((v, "SELECT eof flag"));
    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"));
    sqlite3VdbeJumpHere(v, j1);                          /* label B: */

    regFromSelect = dest.iMem;
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;

      int addrTop;     /* Label "L" */
      int addrIf;      /* Address of jump to M */

      srcTab = pParse->nTab++;
      regRec = sqlite3GetTempReg(pParse);
      regRowid = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
      addrTop = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
      addrIf = sqlite3VdbeAddOp1(v, OP_If, regEof);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
      sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regRowid);
      sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regRowid);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, addrTop);
      sqlite3VdbeJumpHere(v, addrIf);
      sqlite3ReleaseTempReg(pParse, regRec);

    **
    **      C: yield X
    **         if EOF goto D
    **         insert the select result into <table> from R..R+n
    **         goto C
    **      D: ...
    */
    addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iParm);
    addrInsTop = sqlite3VdbeAddOp1(v, OP_If, regEof);
  }

  /* Allocate registers for holding the rowid of the new row,
  ** the content of the new row, and the assemblied row record.
  */
  regRecord = ++pParse->nMem;

**    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 1.434 2008/06/24 00:32:36 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.

/*
** Initialize a SelectDest structure.
*/
void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
  pDest->eDest = eDest;
  pDest->iParm = iParm;

  pDest->affinity = 0;
  pDest->iMem = 0;
  pDest->nMem = 0;
}


/*

  pNew->pHaving = pHaving;
  pNew->pOrderBy = pOrderBy;
  pNew->isDistinct = isDistinct;
  pNew->op = TK_SELECT;
  assert( pOffset==0 || pLimit!=0 );
  pNew->pLimit = pLimit;
  pNew->pOffset = pOffset;


  pNew->addrOpenEphm[0] = -1;
  pNew->addrOpenEphm[1] = -1;
  pNew->addrOpenEphm[2] = -1;
  if( pNew==&standin) {
    clearSelect(pNew);
    pNew = 0;
  }

  sqlite3ExprCodeExprList(pParse, pOrderBy, regBase, 0);
  sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, regBase+nExpr);
  sqlite3ExprCodeMove(pParse, regData, regBase+nExpr+1, 1);
  sqlite3VdbeAddOp3(v, OP_MakeRecord, regBase, nExpr + 2, regRecord);
  sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, regRecord);
  sqlite3ReleaseTempReg(pParse, regRecord);
  sqlite3ReleaseTempRange(pParse, regBase, nExpr+2);
  if( pSelect->iLimit ){
    int addr1, addr2;
    int iLimit;
    if( pSelect->pOffset ){
      iLimit = pSelect->iOffset+1;
    }else{
      iLimit = pSelect->iLimit;
    }
    addr1 = sqlite3VdbeAddOp1(v, OP_IfZero, iLimit);
    sqlite3VdbeAddOp2(v, OP_AddImm, iLimit, -1);
    addr2 = sqlite3VdbeAddOp0(v, OP_Goto);
    sqlite3VdbeJumpHere(v, addr1);
    sqlite3VdbeAddOp1(v, OP_Last, pOrderBy->iECursor);
    sqlite3VdbeAddOp1(v, OP_Delete, pOrderBy->iECursor);
    sqlite3VdbeJumpHere(v, addr2);
    pSelect->iLimit = 0;
  }
}

/*
** Add code to implement the OFFSET
*/
static void codeOffset(
  Vdbe *v,          /* Generate code into this VM */
  Select *p,        /* The SELECT statement being coded */
  int iContinue     /* Jump here to skip the current record */
){
  if( p->iOffset && iContinue!=0 ){
    int addr;
    sqlite3VdbeAddOp2(v, OP_AddImm, p->iOffset, -1);
    addr = sqlite3VdbeAddOp1(v, OP_IfNeg, p->iOffset);
    sqlite3VdbeAddOp2(v, OP_Goto, 0, iContinue);
    VdbeComment((v, "skip OFFSET records"));
    sqlite3VdbeJumpHere(v, addr);
  }

    case SRT_Callback: {
      if( pOrderBy ){
        int r1 = sqlite3GetTempReg(pParse);
        sqlite3VdbeAddOp3(v, OP_MakeRecord, regResult, nColumn, r1);
        pushOntoSorter(pParse, pOrderBy, p, r1);
        sqlite3ReleaseTempReg(pParse, r1);
      }else if( eDest==SRT_Coroutine ){
        sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
      }else{
        sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nColumn);
        sqlite3ExprCacheAffinityChange(pParse, regResult, nColumn);
      }
      break;
    }

      break;
    }
#endif
  }

  /* Jump to the end of the loop if the LIMIT is reached.
  */
  if( p->iLimit && pOrderBy==0 ){
    sqlite3VdbeAddOp2(v, OP_AddImm, p->iLimit, -1);
    sqlite3VdbeAddOp2(v, OP_IfZero, p->iLimit, iBreak);
  }
}

/*
** Given an expression list, generate a KeyInfo structure that records

        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);

  return rc;
}

/*
** pE is a pointer to an expression which is a single term in
** ORDER BY or GROUP BY clause.
**
** At the point this routine is called, we already know that the
** ORDER BY term is not an integer index into the result set.  That

** casee is handled by the calling routine.
**
** If pE is a well-formed expression and the SELECT statement
** is not compound, then return 0.  This indicates to the
** caller that it should sort by the value of the ORDER BY
** expression.
**
** If the SELECT is compound, then attempt to match pE against

  int isCompound,    /* True if this is a compound SELECT */
  u8 *pHasAgg        /* True if expression contains aggregate functions */
){
  int i;             /* Loop counter */
  ExprList *pEList;  /* The columns of the result set */
  NameContext nc;    /* Name context for resolving pE */

  assert( sqlite3ExprIsInteger(pE, &i)==0 );


  pEList = pSelect->pEList;











  /* If the term is a simple identifier that try to match that identifier
  ** against a column name in the result set.
  */
  if( pE->op==TK_ID || (pE->op==TK_STRING && pE->token.z[0]!='\'') ){
    sqlite3 *db = pParse->db;
    char *zCol = sqlite3NameFromToken(db, &pE->token);

  pEList = pSelect->pEList;
  if( pEList==0 ){
    return 0;
  }
  for(i=0; i<pOrderBy->nExpr; i++){
    int iCol;
    Expr *pE = pOrderBy->a[i].pExpr;

    if( sqlite3ExprIsInteger(pE, &iCol) ){


      if( iCol<=0 || iCol>pEList->nExpr ){
        const char *zType = isOrder ? "ORDER" : "GROUP";
        sqlite3ErrorMsg(pParse, 
           "%r %s BY term out of range - should be "
           "between 1 and %d", i+1, zType, pEList->nExpr);
        return 1;
      }
    }else{
      iCol = matchOrderByTermToExprList(pParse, pSelect, pE, i+1, 0, pHasAgg);
      if( iCol<0 ){
        return 1;
      }
    }
    if( iCol>0 ){
      CollSeq *pColl = pE->pColl;
      int flags = pE->flags & EP_ExpCollate;
      sqlite3ExprDelete(pE);
      pE = sqlite3ExprDup(db, pEList->a[iCol-1].pExpr);
      pOrderBy->a[i].pExpr = pE;
      if( pE && pColl && flags ){
        pE->pColl = pColl;
        pE->flags |= flags;
      }
    }
  }
  return 0;
}

/*
** Analyze and ORDER BY or GROUP BY clause in a SELECT statement.  Return
** the number of errors seen.
**
** If iTable>0 then make the N-th term of the ORDER BY clause refer to
** the N-th column of table iTable.
**
** If iTable==0 then transform each term of the ORDER BY clause to refer
** to a column of the result set by number.

*/
static int processCompoundOrderBy(
  Parse *pParse,        /* Parsing context.  Leave error messages here */
  Select *pSelect,      /* The SELECT statement containing the ORDER BY */
  int iTable            /* Output table for compound SELECT statements */
){
  int i;

    pOrderBy->a[i].done = 0;
  }
  while( pSelect->pPrior ){
    pSelect = pSelect->pPrior;
  }
  while( pSelect && moreToDo ){
    moreToDo = 0;
    pEList = pSelect->pEList;
    if( pEList==0 ){
      return 1;
    }
    for(i=0; i<pOrderBy->nExpr; i++){
      int iCol = -1;
      Expr *pE, *pDup;
      if( pOrderBy->a[i].done ) continue;
      pE = pOrderBy->a[i].pExpr;
      if( sqlite3ExprIsInteger(pE, &iCol) ){
        if( iCol<0 || iCol>pEList->nExpr ){
          sqlite3ErrorMsg(pParse, 
             "%r ORDER BY term out of range - should be "
             "between 1 and %d", i+1, pEList->nExpr);
          return 1;
        }
      }else{
        pDup = sqlite3ExprDup(db, pE);
        if( !db->mallocFailed ){
          assert(pDup);
          iCol = matchOrderByTermToExprList(pParse, pSelect, pDup, i+1, 1, 0);
        }
        sqlite3ExprDelete(pDup);
        if( iCol<0 ){
          return 1;
        }



      }
      if( iCol>0 ){





        if( iTable ){
          pE->op = TK_COLUMN;
          pE->iTable = iTable;
          pE->iAgg = -1;
          pE->iColumn = iCol-1;
          pE->pTab = 0;
        }else{
          pE->op = TK_INTEGER;
          pE->flags |= EP_IntValue;
          pE->iTable = iCol;
        }
        pOrderBy->a[i].done = 1;
      }else{
        moreToDo = 1;
      }
    }
    pSelect = pSelect->pNext;
  }

        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);
        p->pPrior = pPrior;
        if( rc ){
          goto multi_select_end;

      ** Be sure to delete p->pOrderBy, therefore, to avoid a memory leak. */
      sqlite3ExprListDelete(p->pOrderBy);
      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;
      }


      /* Convert the data in the temporary table into whatever form
      ** it is that we currently need.

multi_select_end:
  pDest->iMem = dest.iMem;
  pDest->nMem = dest.nMem;
  return rc;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */


/*
** Code an output subroutine for a coroutine implementation of a
** SELECT statment.
*/
static int outputSubroutine(
  Parse *pParse,          /* Parsing context */
  Select *p,              /* The SELECT statement */
  SelectDest *pIn,        /* Coroutine supplying data */
  SelectDest *pDest,      /* Where to send the data */
  int regReturn,          /* The return address register */
  int iBreak              /* Jump here if we hit the LIMIT */
){
  Vdbe *v = pParse->pVdbe;
  int iContinue;
  int addr;
  if( v==0 ) return 0;


  addr = sqlite3VdbeCurrentAddr(v);
  iContinue = sqlite3VdbeMakeLabel(v);

  codeOffset(v, p, iContinue);

  switch( pDest->eDest ){
    /* Store the result as data using a unique key.
    */
    case SRT_Table:
    case SRT_EphemTab: {
      int r1 = sqlite3GetTempReg(pParse);
      int r2 = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp3(v, OP_MakeRecord, pIn->iMem, pIn->nMem, r1);
      sqlite3VdbeAddOp2(v, OP_NewRowid, pDest->iParm, r2);
      sqlite3VdbeAddOp3(v, OP_Insert, pDest->iParm, r1, r2);
      sqlite3VdbeChangeP5(v, OPFLAG_APPEND);
      sqlite3ReleaseTempReg(pParse, r2);
      sqlite3ReleaseTempReg(pParse, r1);
      break;
    }

#ifndef SQLITE_OMIT_SUBQUERY
    /* If we are creating a set for an "expr IN (SELECT ...)" construct,
    ** then there should be a single item on the stack.  Write this
    ** item into the set table with bogus data.
    */
    case SRT_Set: {
      int addr2, r1;
      assert( pIn->nMem==1 );
      addr2 = sqlite3VdbeAddOp1(v, OP_IsNull, pIn->iMem);
      p->affinity = 
         sqlite3CompareAffinity(p->pEList->a[0].pExpr, pDest->affinity);
      r1 = sqlite3GetTempReg(pParse);
      sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iMem, 1, r1, &p->affinity, 1);
      sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, 1);
      sqlite3VdbeAddOp2(v, OP_IdxInsert, pDest->iParm, r1);
      sqlite3ReleaseTempReg(pParse, r1);
      sqlite3VdbeJumpHere(v, addr2);
      break;
    }

    /* If any row exist in the result set, record that fact and abort.
    */
    case SRT_Exists: {
      sqlite3VdbeAddOp2(v, OP_Integer, 1, pDest->iParm);
      /* The LIMIT clause will terminate the loop for us */
      break;
    }

    /* If this is a scalar select that is part of an expression, then
    ** store the results in the appropriate memory cell and break out
    ** of the scan loop.
    */
    case SRT_Mem: {
      assert( pIn->nMem==1 );
      sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iParm, 1);
      /* The LIMIT clause will jump out of the loop for us */
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    /* Send the data to the callback function or to a subroutine.  In the
    ** case of a subroutine, the subroutine itself is responsible for
    ** popping the data from the stack.
    */
    case SRT_Coroutine: {
      if( pDest->iMem==0 ){
        pDest->iMem = sqlite3GetTempRange(pParse, pIn->nMem);
        pDest->nMem = pIn->nMem;
      }
      sqlite3ExprCodeMove(pParse, pIn->iMem, pDest->iMem, pDest->nMem);
      sqlite3VdbeAddOp1(v, OP_Yield, pDest->iParm);
      break;
    }

    case SRT_Callback: {
      sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iMem, pIn->nMem);
      sqlite3ExprCacheAffinityChange(pParse, pIn->iMem, pIn->nMem);

      break;
    }

#if !defined(SQLITE_OMIT_TRIGGER)
    /* Discard the results.  This is used for SELECT statements inside
    ** the body of a TRIGGER.  The purpose of such selects is to call
    ** user-defined functions that have side effects.  We do not care
    ** about the actual results of the select.
    */
    default: {
      break;
    }
#endif
  }

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

  /* Advance the coroutine to its next value.
  */
  sqlite3VdbeResolveLabel(v, iContinue);
  sqlite3VdbeAddOp1(v, OP_Yield, pIn->iParm);

  /* Generate the subroutine return
  */
  sqlite3VdbeAddOp1(v, OP_Return, regReturn);

  return addr;
}

/*
** Alternative compound select code generator for cases when there
** is an ORDER BY clause.
**
** We assume a query of the following form:

*/
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 */
){

  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 */
  int regEofA;          /* Flag to indicate when select-A is complete */
  int regAddrB;         /* Address register for select-B coroutine */
  int regEofB;          /* Flag to indicate when select-B is complete */
  int addrSelectA;      /* Address of the select-A coroutine */
  int addrSelectB;      /* Address of the select-B coroutine */
  int regOutA;          /* Address register for the output-A subroutine */
  int regOutB;          /* Address register for the output-B subroutine */
  int addrOutA;         /* Address of the output-A subroutine */
  int addrOutB;         /* Address of the output-B subroutine */
  int addrEofA;         /* Address of the select-A-exhausted subroutine */
  int addrEofB;         /* Address of the select-B-exhausted subroutine */
  int addrAltB;         /* Address of the A<B subroutine */
  int addrAeqB;         /* Address of the A==B subroutine */
  int addrAgtB;         /* Address of the A>B subroutine */
  int regLimitA;        /* Limit register for select-A */
  int regLimitB;        /* Limit register for select-A */
  int savedLimit;       /* Saved value of p->iLimit */
  int savedOffset;      /* Saved value of p->iOffset */
  int labelCmpr;        /* Label for the start of the merge algorithm */
  int labelEnd;         /* Label for the end of the overall SELECT stmt */
  int j1, j2, j3;       /* Jump instructions that get retargetted */
  int op;               /* One of TK_ALL, TK_UNION, TK_EXCEPT, TK_INTERSECT */
  KeyInfo *pKeyInfo;    /* Type data for comparisons */
  int p4type;           /* P4 type used for pKeyInfo */
  u8 NotUsed;           /* Dummy variable */

  assert( p->pOrderBy!=0 );
  v = pParse->pVdbe;
  if( v==0 ) return SQLITE_NOMEM;
  labelEnd = sqlite3VdbeMakeLabel(v);
  labelCmpr = sqlite3VdbeMakeLabel(v);
  pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
  p4type = P4_KEYINFO_HANDOFF;

  /* Patch up the ORDER BY clause
  */
  op = p->op;  
  pPrior = p->pPrior;
  assert( pPrior->pOrderBy==0 );
  if( processCompoundOrderBy(pParse, p, 0) ){
    return SQLITE_ERROR;
  }
  pPrior->pOrderBy = sqlite3ExprListDup(pParse->db, p->pOrderBy);
 
  /* Separate the left and the right query from one another
  */
  p->pPrior = 0;
  pPrior->pRightmost = 0;
  processOrderGroupBy(pParse, p, p->pOrderBy, 1, &NotUsed);
  processOrderGroupBy(pParse, pPrior, pPrior->pOrderBy, 1, &NotUsed);
  
  /* Compute the limit registers */
  computeLimitRegisters(pParse, p, labelEnd);
  if( p->iLimit ){
    regLimitA = ++pParse->nMem;
    regLimitB = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_Copy, p->iOffset ? p->iOffset+1 : p->iLimit,
                                  regLimitA);
    sqlite3VdbeAddOp2(v, OP_Copy, regLimitA, regLimitB);
  }else{
    regLimitA = regLimitB = 0;
  }

  regAddrA = ++pParse->nMem;
  regEofA = ++pParse->nMem;
  regAddrB = ++pParse->nMem;
  regEofB = ++pParse->nMem;
  regOutA = ++pParse->nMem;
  regOutB = ++pParse->nMem;
  sqlite3SelectDestInit(&destA, SRT_Coroutine, regAddrA);
  sqlite3SelectDestInit(&destB, SRT_Coroutine, regAddrB);

  /* Jump past the various subroutines and coroutines to the main
  ** merge loop
  */
  j1 = sqlite3VdbeAddOp0(v, OP_Goto);
  addrSelectA = sqlite3VdbeCurrentAddr(v);

  /* 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
  ** select as the next output row of the compound select and then
  ** advances the A select to its next row
  */
  VdbeNoopComment((v, "Output routine for A"));
  addrOutA = outputSubroutine(pParse, p, &destA, pDest, regOutA, labelEnd);
  
  /* Generate a subroutine that outputs the current row of the B
  ** select as the next output row of the compound select and then
  ** advances the B select to its next row
  */
  VdbeNoopComment((v, "Output routine for B"));
  addrOutB = outputSubroutine(pParse, p, &destB, pDest, regOutB, labelEnd);

  /* Generate a subroutine to run when the results from select A
  ** are exhausted and only data in select B remains.
  */
  VdbeNoopComment((v, "eof-A subroutine"));
  addrEofA = sqlite3VdbeCurrentAddr(v);
  if( op==TK_EXCEPT || op==TK_INTERSECT ){
    sqlite3VdbeAddOp2(v, OP_Goto, 0, labelEnd);
  }else{  


    if( op==TK_ALL ){
      j2 = sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
      sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);

      sqlite3VdbeAddOp2(v, OP_Goto, 0, j2);
    }else{
      assert( op==TK_UNION );

      sqlite3ExprCodeCopy(pParse, destB.iMem, destA.iMem, destB.nMem);
      j2 = sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);

      sqlite3VdbeAddOp2(v, OP_If, regEofB, labelEnd);
      sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, destB.nMem,
                           (char*)pKeyInfo, p4type);
      p4type = P4_KEYINFO_STATIC;
      sqlite3VdbeAddOp3(v, OP_Jump, j2, j2+4, j2);
      sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, j2+1);
    }
  }


  /* Generate a subroutine to run when the results from select B
  ** are exhausted and only data in select A remains.
  */
  if( op==TK_INTERSECT ){
    addrEofB = addrEofA;
  }else{  
    VdbeNoopComment((v, "eof-B subroutine"));
    addrEofB = sqlite3VdbeCurrentAddr(v);
    if( op==TK_ALL || op==TK_EXCEPT ){
      j2 = sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
      sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, j2);
    }else{
      assert( op==TK_UNION );
      sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
      sqlite3ExprCodeCopy(pParse, destA.iMem, destB.iMem, destA.nMem);
      j2 = sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
      sqlite3VdbeAddOp2(v, OP_If, regEofA, labelEnd);
      sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, destB.nMem,
                           (char*)pKeyInfo, p4type);
      p4type = P4_KEYINFO_STATIC;
      sqlite3VdbeAddOp3(v, OP_Jump, j2, j2+4, j2);
      sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, j2+1);









    }
  }

  /* Generate code to handle the case of A<B
  */
  VdbeNoopComment((v, "A-lt-B subroutine"));
  addrAltB = sqlite3VdbeCurrentAddr(v);
  if( op==TK_INTERSECT ){
    sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
  }else{
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
  }

  sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);

  /* Generate code to handle the case of A==B
  */
  if( op==TK_ALL ){
    addrAeqB = addrAltB;
  }else{
    VdbeNoopComment((v, "A-eq-B subroutine"));
    addrAeqB = sqlite3VdbeCurrentAddr(v);
    if( op==TK_INTERSECT ){

      sqlite3VdbeAddOp2(v, OP_Gosub, regOutA, addrOutA);
      j2 = sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
      sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
      sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, destA.nMem,
                           (char*)pKeyInfo, p4type);
      p4type = P4_KEYINFO_STATIC;
      j3 = sqlite3VdbeCurrentAddr(v)+1;
      sqlite3VdbeAddOp3(v, OP_Jump, j3, j2, j3);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
    }else{
      sqlite3VdbeAddOp1(v, OP_Yield, regAddrA);
      sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);
    }
  }

  /* Generate code to handle the case of A>B
  */
  VdbeNoopComment((v, "A-gt-B subroutine"));
  addrAgtB = sqlite3VdbeCurrentAddr(v);
  if( op==TK_ALL || op==TK_UNION ){
    sqlite3VdbeAddOp2(v, OP_Gosub, regOutB, addrOutB);
  }else{
    sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
  }
  sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);
  sqlite3VdbeAddOp2(v, OP_Goto, 0, labelCmpr);

  /* This code runs once to initialize everything.
  */
  sqlite3VdbeJumpHere(v, j1);
  sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofA);
  sqlite3VdbeAddOp2(v, OP_Integer, 0, regEofB);
  sqlite3VdbeAddOp2(v, OP_Integer, addrSelectB, regAddrB);
  sqlite3VdbeAddOp2(v, OP_Gosub, regAddrA, addrSelectA);

  sqlite3VdbeAddOp2(v, OP_If, regEofA, addrEofA);
  sqlite3VdbeAddOp1(v, OP_Yield, regAddrB);
  sqlite3VdbeAddOp2(v, OP_If, regEofB, addrEofB);

  /* Implement the main merge loop
  */
  sqlite3VdbeResolveLabel(v, labelCmpr);
  sqlite3VdbeAddOp4(v, OP_Compare, destA.iMem, destB.iMem, destA.nMem,
                         (char*)pKeyInfo, p4type);
  p4type = P4_KEYINFO_STATIC;
  sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB);

  /* Jump to the this point in order to terminate the query.
  */
  sqlite3VdbeResolveLabel(v, labelEnd);

  /* Set the number of output columns
  */
  if( pDest->eDest==SRT_Callback ){
    Select *pFirst = p;
    while( pFirst->pPrior ) pFirst = pFirst->pPrior;
    generateColumnNames(pParse, 0, pFirst->pEList);
  }

  /* Free the KeyInfo if unused.
  */
  if( p4type==P4_KEYINFO_HANDOFF ){
    sqlite3_free(pKeyInfo);
  }


  /*** TBD:  Insert subroutine calls to close cursors on incomplete
  **** subqueries ****/
  return SQLITE_OK;
}

#ifndef SQLITE_OMIT_VIEW
/* Forward Declarations */
static void substExprList(sqlite3*, ExprList*, int, ExprList*);
static void substSelect(sqlite3*, Select *, int, ExprList *);

/*

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    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 1.725 2008/06/24 00:32:36 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if we're using the
** autoconf-based build

#define EP_Distinct   0x0010  /* Aggregate function with DISTINCT keyword */
#define EP_VarSelect  0x0020  /* pSelect is correlated, not constant */
#define EP_Dequoted   0x0040  /* True if the string has been dequoted */
#define EP_InfixFunc  0x0080  /* True for an infix function: LIKE, GLOB, etc */
#define EP_ExpCollate 0x0100  /* Collating sequence specified explicitly */
#define EP_AnyAff     0x0200  /* Can take a cached column of any affinity */
#define EP_FixedDest  0x0400  /* Result needed in a specific register */
#define EP_IntValue   0x0800  /* Integer value contained in iTable */
/*
** These macros can be used to test, set, or clear bits in the 
** Expr.flags field.
*/
#define ExprHasProperty(E,P)     (((E)->flags&(P))==(P))
#define ExprHasAnyProperty(E,P)  (((E)->flags&(P))!=0)
#define ExprSetProperty(E,P)     (E)->flags|=(P)

** comments above sqlite3Select() for details.
*/
typedef struct SelectDest SelectDest;
struct SelectDest {
  u8 eDest;         /* How to dispose of the results */
  u8 affinity;      /* Affinity used when eDest==SRT_Set */
  int iParm;        /* A parameter used by the eDest disposal method */

  int iMem;         /* Base register where results are written */
  int nMem;         /* Number of registers allocated */

};

/*
** An SQL parser context.  A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
**

void sqlite3OpenTable(Parse*, int iCur, int iDb, Table*, int);
void sqlite3DeleteFrom(Parse*, SrcList*, Expr*);
void sqlite3Update(Parse*, SrcList*, ExprList*, Expr*, int);
WhereInfo *sqlite3WhereBegin(Parse*, SrcList*, Expr*, ExprList**, u8);
void sqlite3WhereEnd(WhereInfo*);
int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, int);
void sqlite3ExprCodeMove(Parse*, int, int, int);
void sqlite3ExprCodeCopy(Parse*, int, int, int);
void sqlite3ExprClearColumnCache(Parse*, int);
void sqlite3ExprCacheAffinityChange(Parse*, int, int);
int sqlite3ExprWritableRegister(Parse*,int,int);
void sqlite3ExprHardCopy(Parse*,int,int);
int sqlite3ExprCode(Parse*, Expr*, int);
int sqlite3ExprCodeTemp(Parse*, Expr*, int*);
int sqlite3ExprCodeTarget(Parse*, Expr*, int);

# 2001 September 15
#
# The author disclaims copyright to this source code.  In place of
# a legal notice, here is a blessing:
#
#    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.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the SELECT statement.
#
# $Id: select1.test,v 1.59 2008/06/24 00:32:36 drh Exp $

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

# Try to select on a non-existant table.
#
do_test select1-1.1 {

   execsql {
     SELECT a FROM t6 WHERE b IN 
        (SELECT b FROM t6 WHERE a<='b' UNION SELECT '3' AS x
                 ORDER BY 1 DESC LIMIT 1)
   }
} {d}
do_test select1-6.22 {
breakpoint
   execsql {
     SELECT a FROM t6 WHERE b IN 
        (SELECT b FROM t6 WHERE a<='b' UNION SELECT '3' AS x
                 ORDER BY b LIMIT 2)
     ORDER BY a;
   }
} {a b}

do_test select1-14.2 {
  execsql { 
    SELECT 10 IN (SELECT rowid FROM sqlite_master);
  }
} {0}

finish_test