SQLite

** when syntax rules are reduced.  The routines in this file handle the
** following kinds of SQL syntax:
**
**     CREATE TABLE
**     DROP TABLE
**     CREATE INDEX
**     DROP INDEX
**     creating ID lists
**     COPY
**     VACUUM
**     BEGIN TRANSACTION
**     COMMIT
**     ROLLBACK
**     PRAGMA
**
** $Id: build.c,v 1.81 2002/03/02 17:04:08 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** This routine is called after a single SQL statement has been
** parsed and we want to execute the VDBE code to implement 

      sqliteVdbeAddOp(v, OP_SetCookie, db->next_cookie, 0);
      sqliteVdbeAddOp(v, OP_Close, 0, 0);
    }
    if( pSelect ){
      int op = p->isTemp ? OP_OpenWrAux : OP_OpenWrite;
      sqliteVdbeAddOp(v, op, 1, 0);
      pParse->nTab = 2;
      sqliteSelect(pParse, pSelect, SRT_Table, 1, 0, 0, 0);
    }
    sqliteEndWriteOperation(pParse);
  }
}

/*
** The parser calls this routine in order to create a new VIEW

**    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 DELETE FROM statements.
**
** $Id: delete.c,v 1.28 2002/03/02 17:04:08 drh Exp $
*/
#include "sqliteInt.h"


/*
** Given a table name, find the corresponding table and make sure the
** table is writeable.  Generate an error and return NULL if not.  If

  */
  pTabList = sqliteTableTokenToIdList(pParse, pTableName);
  if( pTabList==0 ) goto delete_from_cleanup;
  pTab = pTabList->a[0].pTab;

  /* Resolve the column names in all the expressions.
  */
  base = pParse->nTab++;
  if( pWhere ){

    if( sqliteExprResolveIds(pParse, base, pTabList, 0, pWhere) ){
      goto delete_from_cleanup;
    }
    if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
      goto delete_from_cleanup;
    }
  }

  if( pWhere==0 ){
    if( db->flags & SQLITE_CountRows ){
      /* If counting rows deleted, just count the total number of
      ** entries in the table. */
      int endOfLoop = sqliteVdbeMakeLabel(v);
      int addr;
      openOp = pTab->isTemp ? OP_OpenAux : OP_Open;
      assert( base==0 );
      sqliteVdbeAddOp(v, openOp, 0, pTab->tnum);
      sqliteVdbeAddOp(v, OP_Rewind, 0, sqliteVdbeCurrentAddr(v)+2);
      addr = sqliteVdbeAddOp(v, OP_AddImm, 1, 0);
      sqliteVdbeAddOp(v, OP_Next, 0, addr);
      sqliteVdbeResolveLabel(v, endOfLoop);
      sqliteVdbeAddOp(v, OP_Close, 0, 0);
    }
    sqliteVdbeAddOp(v, OP_Clear, pTab->tnum, pTab->isTemp);
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      sqliteVdbeAddOp(v, OP_Clear, pIdx->tnum, pTab->isTemp);
    }
  }

  /* The usual case: There is a WHERE clause so we have to scan through
  ** the table an pick which records to delete.
  */
  else{
    /* Begin the database scan
    */
    pWInfo = sqliteWhereBegin(pParse, base, pTabList, pWhere, 1);
    if( pWInfo==0 ) goto delete_from_cleanup;

    /* Remember the key of every item to be deleted.
    */
    sqliteVdbeAddOp(v, OP_ListWrite, 0, 0);
    if( db->flags & SQLITE_CountRows ){
      sqliteVdbeAddOp(v, OP_AddImm, 1, 0);
    }

    /* End the database scan loop.
    */
    sqliteWhereEnd(pWInfo);

    /* Delete every item whose key was written to the list during the
    ** database scan.  We have to delete items after the scan is complete
    ** because deleting an item can change the scan order.
    */

    sqliteVdbeAddOp(v, OP_ListRewind, 0, 0);
    openOp = pTab->isTemp ? OP_OpenWrAux : OP_OpenWrite;
    sqliteVdbeAddOp(v, openOp, base, pTab->tnum);
    for(i=1, pIdx=pTab->pIndex; pIdx; i++, pIdx=pIdx->pNext){
      sqliteVdbeAddOp(v, openOp, base+i, pIdx->tnum);
    }
    end = sqliteVdbeMakeLabel(v);

**    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 1.52 2002/03/02 17:04:08 drh Exp $
*/
#include "sqliteInt.h"


/*
** Construct a new expression node and return a pointer to it.  Memory
** for this node is obtained from sqliteMalloc().  The calling function

  if( p==0 ) return 0;
  pNew = sqliteMalloc( sizeof(*p) );
  if( pNew==0 ) return 0;
  pNew->op = p->op;
  pNew->pLeft = sqliteExprDup(p->pLeft);
  pNew->pRight = sqliteExprDup(p->pRight);
  pNew->pList = sqliteExprListDup(p->pList);
  pNew->iTable = p->iTable;
  pNew->iColumn = p->iColumn;
  pNew->iAgg = p->iAgg;
  pNew->token = p->token;
  pNew->span = p->span;
  pNew->pSelect = sqliteSelectDup(p->pSelect);
  return pNew;
}
ExprList *sqliteExprListDup(ExprList *p){
  ExprList *pNew;

      }
      return p->pLeft!=0 || p->pRight!=0 || (p->pList && p->pList->nExpr>0);
    }
  }
  return 0;
}



































/*
** Return TRUE if the given string is a row-id column name.
*/
static int sqliteIsRowid(const char *z){
  if( sqliteStrICmp(z, "_ROWID_")==0 ) return 1;
  if( sqliteStrICmp(z, "ROWID")==0 ) return 1;
  if( sqliteStrICmp(z, "OID")==0 ) return 1;
  return 0;
}

/*
** This routine walks an expression tree and resolves references to
** table columns.  Nodes of the form ID.ID or ID resolve into an
** index to the table in the table list and a column offset.  The 
** Expr.opcode for such nodes is changed to TK_COLUMN.  The Expr.iTable
** value is changed to the index of the referenced table in pTabList
** plus the "base" value.  The base value will ultimately become the
** VDBE cursor number for a cursor that is pointing into the referenced
** table.  The Expr.iColumn value is changed to the index of the column 
** of the referenced table.  The Expr.iColumn value for the special
** ROWID column is -1.  Any INTEGER PRIMARY KEY column is tried as an
** alias for ROWID.
**
** We also check for instances of the IN operator.  IN comes in two

** into a memory cell.
**
** Unknown columns or tables provoke an error.  The function returns
** the number of errors seen and leaves an error message on pParse->zErrMsg.
*/
int sqliteExprResolveIds(
  Parse *pParse,     /* The parser context */
  int base,          /* VDBE cursor number for first entry in pTabList */
  IdList *pTabList,  /* List of tables used to resolve column names */
  ExprList *pEList,  /* List of expressions used to resolve "AS" */
  Expr *pExpr        /* The expression to be analyzed. */
){
  if( pExpr==0 || pTabList==0 ) return 0;
  assert( base+pTabList->nId<=pParse->nTab );
  switch( pExpr->op ){
    /* A lone identifier.  Try and match it as follows:
    **
    **     1.  To the name of a column of one of the tables in pTabList
    **
    **     2.  To the right side of an AS keyword in the column list of
    **         a SELECT statement.  (For example, match against 'x' in

      for(i=0; i<pTabList->nId; i++){
        int j;
        Table *pTab = pTabList->a[i].pTab;
        if( pTab==0 ) continue;
        for(j=0; j<pTab->nCol; j++){
          if( sqliteStrICmp(pTab->aCol[j].zName, z)==0 ){
            cnt++;
            pExpr->iTable = i + base;
            if( j==pTab->iPKey ){
              /* Substitute the record number for the INTEGER PRIMARY KEY */
              pExpr->iColumn = -1;
            }else{
              pExpr->iColumn = j;
            }
            pExpr->op = TK_COLUMN;

            pExpr->iColumn = j;
            pExpr->pLeft = pEList->a[j].pExpr;
          }
        } 
      }
      if( cnt==0 && sqliteIsRowid(z) ){
        pExpr->iColumn = -1;
        pExpr->iTable = base;
        cnt = 1 + (pTabList->nId>1);
        pExpr->op = TK_COLUMN;
      }
      sqliteFree(z);
      if( cnt==0 ){
        sqliteSetNString(&pParse->zErrMsg, "no such column: ", -1,  
          pExpr->token.z, pExpr->token.n, 0);

        if( pTab==0 ) continue;
        if( pTabList->a[i].zAlias ){
          zTab = pTabList->a[i].zAlias;
        }else{
          zTab = pTab->zName;
        }
        if( sqliteStrICmp(zTab, zLeft)!=0 ) continue;
        if( 0==(cntTab++) ) pExpr->iTable = i + base;
        for(j=0; j<pTab->nCol; j++){
          if( sqliteStrICmp(pTab->aCol[j].zName, zRight)==0 ){
            cnt++;
            pExpr->iTable = i + base;
            if( j==pTab->iPKey ){
              /* Substitute the record number for the INTEGER PRIMARY KEY */
              pExpr->iColumn = -1;
            }else{
              pExpr->iColumn = j;
            }
          }

      pExpr->op = TK_COLUMN;
      break;
    }

    case TK_IN: {
      Vdbe *v = sqliteGetVdbe(pParse);
      if( v==0 ) return 1;
      if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pExpr->pLeft) ){
        return 1;
      }
      if( pExpr->pSelect ){
        /* Case 1:     expr IN (SELECT ...)
        **
        ** Generate code to write the results of the select into a temporary
        ** table.  The cursor number of the temporary table has already
        ** been put in iTable by sqliteExprResolveInSelect().
        */
        pExpr->iTable = pParse->nTab++;
        sqliteVdbeAddOp(v, OP_OpenTemp, pExpr->iTable, 1);
        sqliteSelect(pParse, pExpr->pSelect, SRT_Set, pExpr->iTable, 0,0,0);
      }else if( pExpr->pList ){
        /* Case 2:     expr IN (exprlist)
        **
        ** Create a set to put the exprlist values in.  The Set id is stored
        ** in iTable.
        */
        int i, iSet;

    case TK_SELECT: {
      /* This has to be a scalar SELECT.  Generate code to put the
      ** value of this select in a memory cell and record the number
      ** of the memory cell in iColumn.
      */
      pExpr->iColumn = pParse->nMem++;
      if( sqliteSelect(pParse, pExpr->pSelect, SRT_Mem, pExpr->iColumn,0,0,0) ){
        return 1;
      }
      break;
    }

    /* For all else, just recursively walk the tree */
    default: {
      if( pExpr->pLeft
      && sqliteExprResolveIds(pParse, base, pTabList, pEList, pExpr->pLeft) ){
        return 1;
      }
      if( pExpr->pRight 
      && sqliteExprResolveIds(pParse, base, pTabList, pEList, pExpr->pRight) ){
        return 1;
      }
      if( pExpr->pList ){
        int i;
        ExprList *pList = pExpr->pList;
        for(i=0; i<pList->nExpr; i++){
          Expr *pArg = pList->a[i].pExpr;
          if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pArg) ){
            return 1;
          }
        }
      }
    }
  }
  return 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 1.46 2002/03/02 17:04:08 drh Exp $
*/
#include "sqliteInt.h"

/*
** This routine is call to handle SQL of the following forms:
**
**    insert into TABLE (IDLIST) values(EXPRLIST)

  ** in a temporary table.  If data is coming from an expression list,
  ** then we just have to count the number of expressions.
  */
  if( pSelect ){
    int rc;
    srcTab = pParse->nTab++;
    sqliteVdbeAddOp(v, OP_OpenTemp, srcTab, 0);
    rc = sqliteSelect(pParse, pSelect, SRT_Table, srcTab, 0,0,0);
    if( rc || pParse->nErr || sqlite_malloc_failed ) goto insert_cleanup;
    assert( pSelect->pEList );
    nColumn = pSelect->pEList->nExpr;
  }else{
    IdList dummy;
    assert( pList!=0 );
    srcTab = -1;
    assert( pList );
    nColumn = pList->nExpr;



    dummy.nId = 0;
    for(i=0; i<nColumn; i++){
      if( sqliteExprResolveIds(pParse, 0, &dummy, 0, pList->a[i].pExpr) ){
        goto insert_cleanup;
      }
    }
  }

  /* Make sure the number of columns in the source data matches the number
  ** of columns to be inserted into the table.

  openOp = pTab->isTemp ? OP_OpenWrAux : OP_OpenWrite;
  sqliteVdbeAddOp(v, openOp, base, pTab->tnum);
  sqliteVdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
  for(idx=1, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, idx++){
    sqliteVdbeAddOp(v, openOp, idx+base, pIdx->tnum);
    sqliteVdbeChangeP3(v, -1, pIdx->zName, P3_STATIC);
  }
  pParse->nTab += idx;

  /* If the data source is a SELECT statement, then we have to create
  ** a loop because there might be multiple rows of data.  If the data
  ** source is an expression list, then exactly one row will be inserted
  ** and the loop is not used.
  */
  if( srcTab>=0 ){

**
*************************************************************************
** 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 1.54 2002/03/02 17:04:08 drh Exp $
*/
%token_prefix TK_
%token_type {Token}
%default_type {Token}
%extra_argument {Parse *pParse}
%syntax_error {
  sqliteSetString(&pParse->zErrMsg,"syntax error",0);

cmd ::= DROP VIEW ids(X). {
  sqliteDropTable(pParse, &X);
}

//////////////////////// The SELECT statement /////////////////////////////////
//
cmd ::= select(X).  {
  sqliteSelect(pParse, X, SRT_Callback, 0, 0, 0, 0);
  sqliteSelectDelete(X);
}

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

**    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 1.71 2002/03/02 17:04:08 drh Exp $
*/
#include "sqliteInt.h"

/*
** Allocate a new Select structure and return a pointer to that
** structure.
*/

}

/*
** Generate code that will tell the VDBE how many columns there
** are in the result and the name for each column.  This information
** is used to provide "argc" and "azCol[]" values in the callback.
*/
static void generateColumnNames(
  Parse *pParse,      /* Parser context */
  int base,           /* VDBE cursor corresponding to first entry in pTabList */
  IdList *pTabList,   /* List of tables */
  ExprList *pEList    /* Expressions defining the result set */
){
  Vdbe *v = pParse->pVdbe;
  int i;
  if( pParse->colNamesSet || v==0 || sqlite_malloc_failed ) return;
  pParse->colNamesSet = 1;
  sqliteVdbeAddOp(v, OP_ColumnCount, pEList->nExpr, 0);
  for(i=0; i<pEList->nExpr; i++){
    Expr *p;

    if( p==0 ) continue;
    showFullNames = (pParse->db->flags & SQLITE_FullColNames)!=0;
    if( p->span.z && p->span.z[0] && !showFullNames ){
      int addr = sqliteVdbeAddOp(v,OP_ColumnName, i, 0);
      sqliteVdbeChangeP3(v, -1, p->span.z, p->span.n);
      sqliteVdbeCompressSpace(v, addr);
    }else if( p->op==TK_COLUMN && pTabList ){
      Table *pTab = pTabList->a[p->iTable - base].pTab;
      char *zCol;
      int iCol = p->iColumn;
      if( iCol<0 ) iCol = pTab->iPKey;
      assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
      zCol = iCol<0 ? "_ROWID_" : pTab->aCol[iCol].zName;
      if( pTabList->nId>1 || showFullNames ){
        char *zName = 0;
        char *zTab;
 
        zTab = pTabList->a[p->iTable - base].zAlias;
        if( showFullNames || zTab==0 ) zTab = pTab->zName;
        sqliteSetString(&zName, zTab, ".", zCol, 0);
        sqliteVdbeAddOp(v, OP_ColumnName, i, 0);
        sqliteVdbeChangeP3(v, -1, zName, strlen(zName));
        sqliteFree(zName);
      }else{
        sqliteVdbeAddOp(v, OP_ColumnName, i, 0);

        }else{
          sqliteVdbeAddOp(v, OP_OpenTemp, unionTab, 0);
        }
      }

      /* Code the SELECT statements to our left
      */
      rc = sqliteSelect(pParse, pPrior, priorOp, unionTab, 0, 0, 0);
      if( rc ) return rc;

      /* 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;
      rc = sqliteSelect(pParse, p, op, unionTab, 0, 0, 0);
      p->pPrior = pPrior;
      if( rc ) return rc;

      /* Convert the data in the temporary table into whatever form
      ** it is that we currently need.
      */      
      if( eDest!=priorOp ){
        int iCont, iBreak, iStart;
        assert( p->pEList );
        generateColumnNames(pParse, p->base, 0, p->pEList);
        iBreak = sqliteVdbeMakeLabel(v);
        iCont = sqliteVdbeMakeLabel(v);
        sqliteVdbeAddOp(v, OP_Rewind, unionTab, iBreak);
        iStart = sqliteVdbeCurrentAddr(v);
        rc = selectInnerLoop(pParse, 0, unionTab, p->pEList->nExpr,
                             p->pOrderBy, -1, eDest, iParm, 
                             iCont, iBreak);

        return 1;
      }
      sqliteVdbeAddOp(v, OP_OpenTemp, tab1, 1);
      sqliteVdbeAddOp(v, OP_KeyAsData, tab1, 1);

      /* Code the SELECTs to our left into temporary table "tab1".
      */
      rc = sqliteSelect(pParse, pPrior, SRT_Union, tab1, 0, 0, 0);
      if( rc ) return rc;

      /* Code the current SELECT into temporary table "tab2"
      */
      sqliteVdbeAddOp(v, OP_OpenTemp, tab2, 1);
      sqliteVdbeAddOp(v, OP_KeyAsData, tab2, 1);
      p->pPrior = 0;
      rc = sqliteSelect(pParse, p, SRT_Union, tab2, 0, 0, 0);
      p->pPrior = pPrior;
      if( rc ) return rc;

      /* Generate code to take the intersection of the two temporary
      ** tables.
      */
      assert( p->pEList );
      generateColumnNames(pParse, p->base, 0, p->pEList);
      iBreak = sqliteVdbeMakeLabel(v);
      iCont = sqliteVdbeMakeLabel(v);
      sqliteVdbeAddOp(v, OP_Rewind, tab1, iBreak);
      iStart = sqliteVdbeAddOp(v, OP_FullKey, tab1, 0);
      sqliteVdbeAddOp(v, OP_NotFound, tab2, iCont);
      rc = selectInnerLoop(pParse, 0, tab1, p->pEList->nExpr,
                             p->pOrderBy, -1, eDest, iParm, 

      selectOpName(p->op), " do not have the same number of result columns", 0);
    pParse->nErr++;
    return 1;
  }
  pParse->nTab = base;
  return 0;
}

/*
** Recursively scan through an expression tree.  For every reference
** to a column in table number iFrom, change that reference to the
** same column in table number iTo.
*/
static void changeTables(Expr *pExpr, int iFrom, int iTo){
  if( pExpr==0 ) return;
  if( pExpr->op==TK_COLUMN && pExpr->iTable==iFrom ){
    pExpr->iTable = iTo;
  }else{
    changeTables(pExpr->pLeft, iFrom, iTo);
    changeTables(pExpr->pRight, iFrom, iTo);
    if( pExpr->pList ){
      int i;
      for(i=0; i<pExpr->pList->nExpr; i++){
        changeTables(pExpr->pList->a[i].pExpr, iFrom, iTo);
      }
    }
  }
}

/*
** Scan through the expression pExpr.  Replace every reference to
** a column in table number iTable with a copy of the corresponding
** entry in pEList.  When make a copy of pEList, change references
** to columns in table iSub into references to table iTable.
**
** This routine is part of the flattening procedure.  A subquery
** whose result set is defined by pEList appears as entry in the
** FROM clause of a SELECT such that the VDBE cursor assigned to that
** FORM clause entry is iTable.  This routine make the necessary 
** changes to pExpr so that it refers directly to the source table
** of the subquery rather the result set of the subquery.
*/
static void substExpr(Expr *pExpr, int iTable, ExprList *pEList, int iSub){
  if( pExpr==0 ) return;
  if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
    Expr *pNew;
    assert( pEList!=0 && pExpr->iColumn>=0 && pExpr->iColumn<pEList->nExpr );
    assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
    pNew = pEList->a[pExpr->iColumn].pExpr;
    assert( pNew!=0 );
    pExpr->op = pNew->op;
    pExpr->pLeft = sqliteExprDup(pNew->pLeft);
    pExpr->pRight = sqliteExprDup(pNew->pRight);
    pExpr->pList = sqliteExprListDup(pNew->pList);
    pExpr->iTable = pNew->iTable;
    pExpr->iColumn = pNew->iColumn;
    pExpr->iAgg = pNew->iAgg;
    if( iSub!=iTable ){
      changeTables(pExpr, iSub, iTable);
    }
  }else{
    static void substExprList(ExprList*,int,ExprList*,int);
    substExpr(pExpr->pLeft, iTable, pEList, iSub);
    substExpr(pExpr->pRight, iTable, pEList, iSub);
    substExprList(pExpr->pList, iTable, pEList, iSub);
  }
}
static void 
substExprList(ExprList *pList, int iTable, ExprList *pEList, int iSub){
  int i;
  if( pList==0 ) return;
  for(i=0; i<pList->nExpr; i++){
    substExpr(pList->a[i].pExpr, iTable, pEList, iSub);
  }
}

/*
** This routine attempts to flatten subqueries in order to speed
** execution.  It returns 1 if it makes changes and 0 if no flattening
** occurs.
**
** To understand the concept of flattening, consider the following
** query:
**
**     SELECT a FROM (SELECT x+y AS a FROM t1 WHERE z<100) WHERE a>5
**
** The default way of implementing this query is to execute the
** subquery first and store the results in a temporary table, then
** run the outer query on that temporary table.  This requires two
** passes over the data.  Furthermore, because the temporary table
** has no indices, the WHERE clause on the outer query cannot be
** optimized.
**
** This routine attempts to rewrite queries such as the above into
** a single flat select, like this:
**
**     SELECT x+y AS a FROM t1 WHERE z<100 AND a>5
**
** The code generated for this simpification gives the same result
** but only has to scan the data once.  And because indices might 
** exist on the table t1, a complete scan of the data might be
** avoided.
**
** Flattening is only attempted if all of the following are true:
**
**   (1)  The subquery and the outer query do not both use aggregates.
**
**   (2)  The subquery is not an aggregate or the outer query is not a join.
**
**   (3)  The subquery is not a join.
**
**   (4)  The subquery is not DISTINCT or the outer query is not a join.
**
**   (5)  The subquery is not DISTINCT or the outer query does not use
**        aggregates.
**
**   (6)  The subquery does not use aggregates or the outer query is not
**        DISTINCT.
**
** In this routine, the "p" parameter is a pointer to the outer query.
** The subquery is p->pSrc->a[iFrom].  isAgg is true if the outer query
** uses aggregates and subqueryIsAgg is true if the subquery uses aggregates.
**
** If flattening is not attempted, this routine is a no-op and return 0.
** If flattening is attempted this routine returns 1.

**
** All of the expression analysis must occur on both the outer query and
** the subquery before this routine runs.
*/
int flattenSubquery(Select *p, int iFrom, int isAgg, int subqueryIsAgg){
  Select *pSub;
  IdList *pSrc, *pSubSrc;
  ExprList *pList;
  int i;
  int iParent, iSub;
  Expr *pWhere;

  /* Check to see if flattening is permitted.  Return 0 if not.
  */
  if( p==0 ) return 0;
  pSrc = p->pSrc;
  assert( pSrc && iFrom>=0 && iFrom<pSrc->nId );
  pSub = pSrc->a[iFrom].pSelect;
  assert( pSub!=0 );
  if( isAgg && subqueryIsAgg ) return 0;
  if( subqueryIsAgg && pSrc->nId>1 ) return 0;
  pSubSrc = pSub->pSrc;
  assert( pSubSrc );
  if( pSubSrc->nId>1 ) return 0;
  if( pSub->isDistinct && pSrc->nId>1 ) return 0;
  if( pSub->isDistinct && isAgg ) return 0;
  if( p->isDistinct && subqueryIsAgg ) return 0;

  /* If we reach this point, it means flatting is permitted for the
  ** i-th entry of the FROM clause in the outer query.
  */
  iParent = p->base + iFrom;
  iSub = pSub->base;

  substExprList(p->pEList, iParent, pSub->pEList, iSub);
  pList = p->pEList;
  for(i=0; i<pList->nExpr; i++){
    if( pList->a[i].zName==0 ){
      Expr *pExpr = pList->a[i].pExpr;
      pList->a[i].zName = sqliteStrNDup(pExpr->span.z, pExpr->span.n);
    }
  }
  substExprList(p->pGroupBy, iParent, pSub->pEList, iSub);
  substExpr(p->pHaving, iParent, pSub->pEList, iSub);
  substExprList(p->pOrderBy, iParent, pSub->pEList, iSub);
  if( pSub->pWhere ){

    pWhere = sqliteExprDup(pSub->pWhere);
    if( iParent!=iSub ){
      changeTables(pWhere, iSub, iParent);
    }
  }else{
    pWhere = 0;
  }
  if( subqueryIsAgg ){
    assert( p->pHaving==0 );
    p->pHaving = pWhere;
    substExpr(p->pHaving, iParent, pSub->pEList, iSub);
  }else if( p->pWhere==0 ){
    p->pWhere = pWhere;
  }else{
    substExpr(p->pWhere, iParent, pSub->pEList, iSub);
    if( pWhere ){

      p->pWhere = sqliteExpr(TK_AND, p->pWhere, pWhere, 0);
    }
  }
  p->isDistinct = p->isDistinct || pSub->isDistinct;
  if( pSrc->a[iFrom].pTab && pSrc->a[iFrom].pTab->isTransient ){
    sqliteDeleteTable(0, pSrc->a[iFrom].pTab);
  }
  pSrc->a[iFrom].pTab = pSubSrc->a[0].pTab;
  pSubSrc->a[0].pTab = 0;
  pSrc->a[iFrom].pSelect = pSubSrc->a[0].pSelect;
  pSubSrc->a[0].pSelect = 0;
  sqliteSelectDelete(pSub);
  return 1;
}

/*
** Analyze the SELECT statement passed in as an argument to see if it
** is a simple min() or max() query.  If it is and this query can be
** satisfied using a single seek to the beginning or end of an index,
** then generate the code for this SELECT return 1.  If this is not a 
** simple min() or max() query, then return 0;

  /* Identify column names if we will be using the callback.  This
  ** step is skipped if the output is going to a table or a memory cell.
  */
  v = sqliteGetVdbe(pParse);
  if( v==0 ) return 0;
  if( eDest==SRT_Callback ){
    generateColumnNames(pParse, p->base, p->pSrc, p->pEList);
  }

  /* Generating code to find the min or the max.  Basically all we have
  ** to do is find the first or the last entry in the chosen index.  If
  ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
  ** or last entry in the main table.
  */
  if( !pParse->schemaVerified && (pParse->db->flags & SQLITE_InTrans)==0 ){
    sqliteVdbeAddOp(v, OP_VerifyCookie, pParse->db->schema_cookie, 0);
    pParse->schemaVerified = 1;
  }
  openOp = pTab->isTemp ? OP_OpenAux : OP_Open;
  base = p->base;
  sqliteVdbeAddOp(v, openOp, base, pTab->tnum);
  sqliteVdbeChangeP3(v, -1, pTab->zName, P3_STATIC);
  if( pIdx==0 ){
    sqliteVdbeAddOp(v, seekOp, base, 0);
  }else{
    sqliteVdbeAddOp(v, openOp, base+1, pIdx->tnum);
    sqliteVdbeChangeP3(v, -1, pIdx->zName, P3_STATIC);

** This routine does NOT free the Select structure passed in.  The
** calling function needs to do that.
*/
int sqliteSelect(
  Parse *pParse,         /* The parser context */
  Select *p,             /* The SELECT statement being coded. */
  int eDest,             /* One of: SRT_Callback Mem Set Union Except */
  int iParm,             /* Save result in this memory location, if >=0 */
  Select *pParent,       /* Another SELECT for which this is a sub-query */
  int parentTab,         /* Index in pParent->pSrc of this query */
  int parentAgg          /* True if pParent uses aggregate functions */
){
  int i;
  WhereInfo *pWInfo;
  Vdbe *v;
  int isAgg = 0;         /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of columns to extract. */
  IdList *pTabList;      /* List of tables to select from */

  pTabList = p->pSrc;
  pWhere = p->pWhere;
  pOrderBy = p->pOrderBy;
  pGroupBy = p->pGroupBy;
  pHaving = p->pHaving;
  isDistinct = p->isDistinct;

  /* Allocate a block of VDBE cursors, one for each table in the FROM clause.
  ** The WHERE processing requires that the cursors for the tables in the
  ** FROM clause be consecutive.
  */
  base = p->base = pParse->nTab;
  pParse->nTab += pTabList->nId;

  /* 
  ** Do not even attempt to generate any code if we have already seen
  ** errors before this routine starts.
  */
  if( pParse->nErr>0 ) goto select_end;

  /* Look up every table in the table list and create an appropriate
  ** columnlist in pEList if there isn't one already.  (The parser leaves
  ** a NULL in the p->pEList if the SQL said "SELECT * FROM ...")
  */
  if( fillInColumnList(pParse, p) ){
    goto select_end;
  }
  pEList = p->pEList;
  if( pEList==0 ) goto select_end;











  /* If writing to memory or generating a set
  ** only a single column may be output.
  */
  if( (eDest==SRT_Mem || eDest==SRT_Set) && pEList->nExpr>1 ){
    sqliteSetString(&pParse->zErrMsg, "only a single result allowed for "
       "a SELECT that is part of an expression", 0);
    pParse->nErr++;
    goto select_end;
  }

  /* ORDER BY is ignored if we are not sending the result to a callback.
  */
  if( eDest!=SRT_Callback ){
    sqliteExprListDelete(p->pOrderBy);
    pOrderBy = p->pOrderBy = 0;
  }



















  /* At this point, we should have allocated all the cursors that we
  ** need to handle subquerys and temporary tables.  

  **
  ** Resolve the column names and do a semantics check on all the expressions.
  */
  for(i=0; i<pEList->nExpr; i++){
    if( sqliteExprResolveIds(pParse, base, pTabList, 0, pEList->a[i].pExpr) ){
      goto select_end;
    }
    if( sqliteExprCheck(pParse, pEList->a[i].pExpr, 1, &isAgg) ){
      goto select_end;
    }
  }
  if( pWhere ){
    if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pWhere) ){
      goto select_end;
    }
    if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
      goto select_end;
    }
  }
  if( pOrderBy ){
    for(i=0; i<pOrderBy->nExpr; i++){
      Expr *pE = pOrderBy->a[i].pExpr;
      if( sqliteExprIsConstant(pE) ){
        sqliteSetString(&pParse->zErrMsg, 
             "ORDER BY expressions should not be constant", 0);
        pParse->nErr++;
        goto select_end;
      }
      if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pE) ){
        goto select_end;
      }
      if( sqliteExprCheck(pParse, pE, isAgg, 0) ){
        goto select_end;
      }
    }
  }
  if( pGroupBy ){
    for(i=0; i<pGroupBy->nExpr; i++){
      Expr *pE = pGroupBy->a[i].pExpr;
      if( sqliteExprIsConstant(pE) ){
        sqliteSetString(&pParse->zErrMsg, 
             "GROUP BY expressions should not be constant", 0);
        pParse->nErr++;
        goto select_end;
      }
      if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pE) ){
        goto select_end;
      }
      if( sqliteExprCheck(pParse, pE, isAgg, 0) ){
        goto select_end;
      }
    }
  }
  if( pHaving ){
    if( pGroupBy==0 ){
      sqliteSetString(&pParse->zErrMsg, "a GROUP BY clause is required "
         "before HAVING", 0);
      pParse->nErr++;
      goto select_end;
    }
    if( sqliteExprResolveIds(pParse, base, pTabList, pEList, pHaving) ){
      goto select_end;
    }
    if( sqliteExprCheck(pParse, pHaving, isAgg, 0) ){
      goto select_end;
    }
  }









  /* Check for the special case of a min() or max() function by itself
  ** in the result set.
  */
  if( simpleMinMaxQuery(pParse, p, eDest, iParm) ){
    rc = 0;
    goto select_end;
  }

  /* Begin generating code.
  */
  v = sqliteGetVdbe(pParse);
  if( v==0 ) goto select_end;

  /* Generate code for all sub-queries in the FROM clause
  */
  for(i=0; i<pTabList->nId; i++){

    if( pTabList->a[i].pSelect==0 ) continue;


    sqliteVdbeAddOp(v, OP_OpenTemp, base+i, 0);
    sqliteSelect(pParse, pTabList->a[i].pSelect, SRT_Table, base+i,
                 p, i, isAgg);
  }

  /* Check to see if this is a subquery that can be "flattened" into its parent.
  ** If flattening is a possiblity, do so and return immediately.  
  */
  if( flattenSubquery(pParent, parentTab, parentAgg, isAgg) ){
    return rc;
  }
  pTabList = p->pSrc;
  pWhere = p->pWhere;
  pOrderBy = p->pOrderBy;
  pGroupBy = p->pGroupBy;
  pHaving = p->pHaving;
  isDistinct = p->isDistinct;

  /* Do an analysis of aggregate expressions.
  */
  sqliteAggregateInfoReset(pParse);
  if( isAgg ){
    assert( pParse->nAgg==0 );
    for(i=0; i<pEList->nExpr; i++){

  }
    

  /* Identify column names if we will be using in the callback.  This
  ** step is skipped if the output is going to a table or a memory cell.
  */
  if( eDest==SRT_Callback ){
    generateColumnNames(pParse, p->base, pTabList, pEList);
  }

  /* Reset the aggregator
  */
  if( isAgg ){
    sqliteVdbeAddOp(v, OP_AggReset, 0, pParse->nAgg);
    for(i=0; i<pParse->nAgg; i++){

  /* Initialize the memory cell to NULL
  */
  if( eDest==SRT_Mem ){
    sqliteVdbeAddOp(v, OP_String, 0, 0);
    sqliteVdbeAddOp(v, OP_MemStore, iParm, 1);
  }

  /* Open a temporary table to use for the distinct set.
  */
  if( isDistinct ){
    distinct = pParse->nTab++;
    sqliteVdbeAddOp(v, OP_OpenTemp, distinct, 1);
  }else{
    distinct = -1;
  }

  /* Begin the database scan
  */
  pWInfo = sqliteWhereBegin(pParse, p->base, pTabList, pWhere, 0);
  if( pWInfo==0 ) goto select_end;

  /* Use the standard inner loop if we are not dealing with
  ** aggregates
  */
  if( !isAgg ){
    if( selectInnerLoop(pParse, pEList, 0, 0, pOrderBy, distinct, eDest, iParm,

  /* If there is an ORDER BY clause, then we need to sort the results
  ** and send them to the callback one by one.
  */
  if( pOrderBy ){
    generateSortTail(v, pEList->nExpr);
  }



  /* Issue a null callback if that is what the user wants.
  */
  if( (pParse->db->flags & SQLITE_NullCallback)!=0 && eDest==SRT_Callback ){
    sqliteVdbeAddOp(v, OP_NullCallback, pEList->nExpr, 0);
  }

  /* The SELECT was successfully coded.   Set the return code to 0
  ** to indicate no errors.
  */
  rc = 0;

  /* Control jumps to here if an error is encountered above, or upon
  ** successful coding of the SELECT.
  */
select_end:
  pParse->nTab = base;
  sqliteAggregateInfoReset(pParse);
  return rc;
}

/*
** 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 1.97 2002/03/02 17:04:08 drh Exp $
*/
#include "sqlite.h"
#include "hash.h"
#include "vdbe.h"
#include "parse.h"
#include "btree.h"
#include <stdio.h>

struct WhereInfo {
  Parse *pParse;
  IdList *pTabList;    /* List of tables in the join */
  int iContinue;       /* Jump here to continue with next record */
  int iBreak;          /* Jump here to break out of the loop */
  int base;            /* Index of first Open opcode */
  int nLevel;          /* Number of nested loop */
  int savedNTab;       /* Value of pParse->nTab before WhereBegin() */
  int peakNTab;        /* Value of pParse->nTab after WhereBegin() */
  WhereLevel a[1];     /* Information about each nest loop in the WHERE */
};

/*
** An instance of the following structure contains all information
** needed to generate code for a single SELECT statement.
**

  ExprList *pGroupBy;    /* The GROUP BY clause */
  Expr *pHaving;         /* The HAVING clause */
  ExprList *pOrderBy;    /* The ORDER BY clause */
  int op;                /* One of: TK_UNION TK_ALL TK_INTERSECT TK_EXCEPT */
  Select *pPrior;        /* Prior select in a compound select statement */
  int nLimit, nOffset;   /* LIMIT and OFFSET values.  -1 means not used */
  char *zSelect;         /* Complete text of the SELECT command */
  int base;              /* Index of VDBE cursor for left-most FROM table */
};

/*
** The results of a select can be distributed in several ways.
*/
#define SRT_Callback     1  /* Invoke a callback with each row of result */
#define SRT_Mem          2  /* Store result in a memory cell */

  Vdbe *pVdbe;         /* An engine for executing database bytecode */
  int colNamesSet;     /* TRUE after OP_ColumnCount has been issued to pVdbe */
  int explain;         /* True if the EXPLAIN flag is found on the query */
  int initFlag;        /* True if reparsing CREATE TABLEs */
  int nameClash;       /* A permanent table name clashes with temp table name */
  int newTnum;         /* Table number to use when reparsing CREATE TABLEs */
  int nErr;            /* Number of errors seen */
  int nTab;            /* Number of previously allocated VDBE cursors */
  int nMem;            /* Number of memory cells used so far */
  int nSet;            /* Number of sets used so far */
  int nAgg;            /* Number of aggregate expressions */
  AggExpr *aAgg;       /* An array of aggregate expressions */
  int useAgg;          /* If true, extract field values from the aggregator
                       ** while generating expressions.  Normally false */
  int schemaVerified;  /* True if an OP_VerifySchema has been coded someplace

void sqliteDeleteTable(sqlite*, Table*);
void sqliteInsert(Parse*, Token*, ExprList*, Select*, IdList*, int);
IdList *sqliteIdListAppend(IdList*, Token*);
void sqliteIdListAddAlias(IdList*, Token*);
void sqliteIdListDelete(IdList*);
void sqliteCreateIndex(Parse*, Token*, Token*, IdList*, int, Token*, Token*);
void sqliteDropIndex(Parse*, Token*);
int sqliteSelect(Parse*, Select*, int, int, Select*, int, int);
Select *sqliteSelectNew(ExprList*,IdList*,Expr*,ExprList*,Expr*,ExprList*,
                        int,int,int);
void sqliteSelectDelete(Select*);
void sqliteSelectUnbind(Select*);
Table *sqliteTableNameToTable(Parse*, const char*);
IdList *sqliteTableTokenToIdList(Parse*, Token*);
void sqliteDeleteFrom(Parse*, Token*, Expr*);
void sqliteUpdate(Parse*, Token*, ExprList*, Expr*, int);
WhereInfo *sqliteWhereBegin(Parse*, int, IdList*, Expr*, int);
void sqliteWhereEnd(WhereInfo*);
void sqliteExprCode(Parse*, Expr*);
void sqliteExprIfTrue(Parse*, Expr*, int);
void sqliteExprIfFalse(Parse*, Expr*, int);
Table *sqliteFindTable(sqlite*,const char*);
Index *sqliteFindIndex(sqlite*,const char*);
void sqliteUnlinkAndDeleteIndex(sqlite*,Index*);
void sqliteCopy(Parse*, Token*, Token*, Token*, int);
void sqliteVacuum(Parse*, Token*);
int sqliteGlobCompare(const unsigned char*,const unsigned char*);
int sqliteLikeCompare(const unsigned char*,const unsigned char*);
char *sqliteTableNameFromToken(Token*);
int sqliteExprCheck(Parse*, Expr*, int, int*);
int sqliteExprCompare(Expr*, Expr*);
int sqliteFuncId(Token*);
int sqliteExprResolveIds(Parse*, int, IdList*, ExprList*, Expr*);

int sqliteExprAnalyzeAggregates(Parse*, Expr*);
Vdbe *sqliteGetVdbe(Parse*);
int sqliteRandomByte(void);
int sqliteRandomInteger(void);
void sqliteBeginTransaction(Parse*, int);
void sqliteCommitTransaction(Parse*);
void sqliteRollbackTransaction(Parse*);

**    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 1.35 2002/03/02 17:04:09 drh Exp $
*/
#include "sqliteInt.h"

/*
** Process an UPDATE statement.
*/
void sqliteUpdate(

  if( aXRef==0 ) goto update_cleanup;
  for(i=0; i<pTab->nCol; i++) aXRef[i] = -1;

  /* Resolve the column names in all the expressions in both the
  ** WHERE clause and in the new values.  Also find the column index
  ** for each column to be updated in the pChanges array.
  */

  base = pParse->nTab++;




  if( pWhere ){
    if( sqliteExprResolveIds(pParse, base, pTabList, 0, pWhere) ){
      goto update_cleanup;
    }
    if( sqliteExprCheck(pParse, pWhere, 0, 0) ){
      goto update_cleanup;
    }
  }
  chngRecno = 0;
  for(i=0; i<pChanges->nExpr; i++){
    if( sqliteExprResolveIds(pParse, base, pTabList, 0, pChanges->a[i].pExpr) ){
      goto update_cleanup;
    }
    if( sqliteExprCheck(pParse, pChanges->a[i].pExpr, 0, 0) ){
      goto update_cleanup;
    }
    for(j=0; j<pTab->nCol; j++){
      if( sqliteStrICmp(pTab->aCol[j].zName, pChanges->a[i].zName)==0 ){

  */
  v = sqliteGetVdbe(pParse);
  if( v==0 ) goto update_cleanup;
  sqliteBeginMultiWriteOperation(pParse);

  /* Begin the database scan
  */
  pWInfo = sqliteWhereBegin(pParse, base, pTabList, pWhere, 1);
  if( pWInfo==0 ) goto update_cleanup;

  /* Remember the index of every item to be updated.
  */
  sqliteVdbeAddOp(v, OP_ListWrite, 0, 0);

  /* End the database scan loop.

  /* Rewind the list of records that need to be updated and
  ** open every index that needs updating.  Note that if any
  ** index could potentially invoke a REPLACE conflict resolution 
  ** action, then we need to open all indices because we might need
  ** to be deleting some records.
  */
  sqliteVdbeAddOp(v, OP_ListRewind, 0, 0);

  openOp = pTab->isTemp ? OP_OpenWrAux : OP_OpenWrite;
  sqliteVdbeAddOp(v, openOp, base, pTab->tnum);
  if( onError==OE_Replace ){
    openAll = 1;
  }else{
    openAll = 0;
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      if( pIdx->onError==OE_Replace ){
        openAll = 1;
        break;
      }
    }
  }
  for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
    if( openAll || aIdxUsed[i] ){
      sqliteVdbeAddOp(v, openOp, base+i+1, pIdx->tnum);
      assert( pParse->nTab==base+i+1 );
    }
    pParse->nTab++;
  }

  /* Loop over every record that needs updating.  We have to load
  ** the old data for each record to be updated because some columns
  ** might not change and we will need to copy the old value.
  ** Also, the old data is needed to delete the old index entires.
  ** So make the cursor point at the old record.

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  Also found here are subroutines
** to generate VDBE code to evaluate expressions.
**
** $Id: where.c,v 1.38 2002/03/02 17:04:09 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.

** if table 1 is used.  And so forth.
**
** In order for this routine to work, the calling function must have
** previously invoked sqliteExprResolveIds() on the expression.  See
** the header comment on that routine for additional information.
**
** "base" is the cursor number (the value of the iTable field) that
** corresponds to the first entry in the table list. 

*/
static int exprTableUsage(int base, Expr *p){
  unsigned int mask = 0;
  if( p==0 ) return 0;
  if( p->op==TK_COLUMN ){
    return 1<< (p->iTable - base);
  }

/*
** The input to this routine is an ExprInfo structure with only the
** "p" field filled in.  The job of this routine is to analyze the
** subexpression and populate all the other fields of the ExprInfo
** structure.
**
** "base" is the cursor number (the value of the iTable field) that
** corresponds to the first entry in the table list.

*/
static void exprAnalyze(int base, ExprInfo *pInfo){
  Expr *pExpr = pInfo->p;
  pInfo->prereqLeft = exprTableUsage(base, pExpr->pLeft);
  pInfo->prereqRight = exprTableUsage(base, pExpr->pRight);
  pInfo->indexable = 0;
  pInfo->idxLeft = -1;

** should invoke sqliteWhereEnd() with the return value of this function
** in order to complete the WHERE clause processing.
**
** If an error occurs, this routine returns NULL.
*/
WhereInfo *sqliteWhereBegin(
  Parse *pParse,       /* The parser context */
  int base,            /* VDBE cursor index for left-most table in pTabList */
  IdList *pTabList,    /* A list of all tables */
  Expr *pWhere,        /* The WHERE clause */
  int pushKey          /* If TRUE, leave the table key on the stack */
){
  int i;                     /* Loop counter */
  WhereInfo *pWInfo;         /* Will become the return value of this function */
  Vdbe *v = pParse->pVdbe;   /* The virtual database engine */
  int brk, cont;             /* Addresses used during code generation */
  int *aOrder;         /* Order in which pTabList entries are searched */
  int nExpr;           /* Number of subexpressions in the WHERE clause */
  int loopMask;        /* One bit set for each outer loop */
  int haveKey;         /* True if KEY is on the stack */


  int aDirect[32];     /* If TRUE, then index this table using ROWID */
  int iDirectEq[32];   /* Term of the form ROWID==X for the N-th table */
  int iDirectLt[32];   /* Term of the form ROWID<X or ROWID<=X */
  int iDirectGt[32];   /* Term of the form ROWID>X or ROWID>=X */
  ExprInfo aExpr[50];  /* The WHERE clause is divided into these expressions */

  /* Allocate space for aOrder[] and aiMem[]. */
  aOrder = sqliteMalloc( sizeof(int) * pTabList->nId );

  /* Allocate and initialize the WhereInfo structure that will become the
  ** return value.
  */
  pWInfo = sqliteMalloc( sizeof(WhereInfo) + pTabList->nId*sizeof(WhereLevel) );
  if( sqlite_malloc_failed ){
    sqliteFree(aOrder);
    sqliteFree(pWInfo);
    return 0;
  }
  pWInfo->pParse = pParse;
  pWInfo->pTabList = pTabList;
  pWInfo->base = base;

  pWInfo->peakNTab = pWInfo->savedNTab = pParse->nTab;

  /* Split the WHERE clause into as many as 32 separate subexpressions
  ** where each subexpression is separated by an AND operator.  Any additional
  ** subexpressions are attached in the aExpr[32] and will not enter
  ** into the query optimizer computations.  32 is chosen as the cutoff
  ** since that is the number of bits in an integer that we use for an
  ** expression-used mask.  

        bestScore = score;
      }
    }
    pWInfo->a[i].pIdx = pBestIdx;
    pWInfo->a[i].score = bestScore;
    loopMask |= 1<<idx;
    if( pBestIdx ){
      pWInfo->a[i].iCur = pParse->nTab++;
      pWInfo->peakNTab = pParse->nTab;
    }
  }

  /* Open all tables in the pTabList and all indices used by those tables.
  */
  for(i=0; i<pTabList->nId; i++){
    int openOp;

    if( pTabList->a[i].pTab->isTransient ) continue;
    pLevel = &pWInfo->a[i];
    sqliteVdbeAddOp(v, OP_Close, base+i, 0);
    if( pLevel->pIdx!=0 ){
      sqliteVdbeAddOp(v, OP_Close, pLevel->iCur, 0);
    }
  }
  if( pWInfo->pParse->nTab==pWInfo->peakNTab ){
    pWInfo->pParse->nTab = pWInfo->savedNTab;
  }
  sqliteFree(pWInfo);
  return;
}

# 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 built-in functions.
#
# $Id: func.test,v 1.9 2002/03/02 17:04:09 drh Exp $

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

# Create a table to work with.
#
do_test func-0.0 {
  execsql {CREATE TABLE tbl1(t1 text)}
  foreach word {this program is free software} {
    execsql "INSERT INTO tbl1 VALUES('$word')"
  }
  execsql {SELECT t1 FROM tbl1 ORDER BY t1}
} {free is program software this}
do_test func-0.1 {
  execsql {
     CREATE TABLE t2(a);
     INSERT INTO t2 VALUES(1);
     INSERT INTO t2 VALUES(NULL);
     INSERT INTO t2 VALUES(345);
     INSERT INTO t2 VALUES(NULL);
     INSERT INTO t2 VALUES(67890);
     SELECT * FROM t2;
  }
} {1 {} 345 {} 67890}

# Check out the length() function
#
do_test func-1.0 {
  execsql {SELECT length(t1) FROM tbl1 ORDER BY t1}
} {4 2 7 8 4}
do_test func-1.1 {
  set r [catch {execsql {SELECT length(*) FROM tbl1 ORDER BY t1}} msg]
  lappend r $msg
} {1 {wrong number of arguments to function length()}}
do_test func-1.2 {
  set r [catch {execsql {SELECT length(t1,5) FROM tbl1 ORDER BY t1}} msg]
  lappend r $msg
} {1 {wrong number of arguments to function length()}}
do_test func-1.3 {
  execsql {SELECT length(t1), count(*) FROM tbl1 GROUP BY length(t1)
           ORDER BY length(t1)}
} {2 1 4 2 7 1 8 1}
do_test func-1.4 {
  execsql {SELECT length(a) FROM t2}
} {1 0 3 0 5}

# Check out the substr() function
#
do_test func-2.0 {
  execsql {SELECT substr(t1,1,2) FROM tbl1 ORDER BY t1}
} {fr is pr so th}
do_test func-2.1 {

} {ee is am re is}
do_test func-2.7 {
  execsql {SELECT substr(t1,-4,2) FROM tbl1 ORDER BY t1}
} {fr {} gr wa th}
do_test func-2.8 {
  execsql {SELECT t1 FROM tbl1 ORDER BY substr(t1,2,20)}
} {this software free program is}
do_test func-2.9 {
  execsql {SELECT substr(a,1,1) FROM t2}
} {1 {} 3 {} 6}
do_test func-2.10 {
  execsql {SELECT substr(a,2,2) FROM t2}
} {{} {} 45 {} 78}

# Only do the following tests if TCL has UTF-8 capabilities and
# the UTF-8 encoding is turned on in the SQLite library.
#
if {[sqlite -encoding]=="UTF-8" && "\u1234"!="u1234"} {

# Put some UTF-8 characters in the database

} "s s o 8"
do_test func-3.9 {
  execsql {SELECT substr(t1,-3,2) FROM tbl1 ORDER BY t1}
} "er in \u1234h F-"
do_test func-3.10 {
  execsql {SELECT substr(t1,-4,3) FROM tbl1 ORDER BY t1}
} "ter ain i\u1234h TF-"
do_test func-3.99 {
  execsql {DELETE FROM tbl1}
  foreach word {this program is free software} {
    execsql "INSERT INTO tbl1 VALUES('$word')"
  }
  execsql {SELECT t1 FROM tbl1}
} {this program is free software}

} ;# End [sqlite -encoding]==UTF-8 and \u1234!=u1234

# Test the abs() and round() functions.
#
do_test func-4.1 {
  execsql {

} {1 {wrong number of arguments to function abs()}}
do_test func-4.3 {
  catchsql {SELECT abs(b) FROM t1 ORDER BY a}
} {0 {2 1.2345678901234 2}}
do_test func-4.4 {
  catchsql {SELECT abs(c) FROM t1 ORDER BY a}
} {0 {3 12345.67890 5}}
do_test func-4.4.1 {
  execsql {SELECT abs(a) FROM t2}
} {1 {} 345 {} 67890}
do_test func-4.4.2 {
  execsql {SELECT abs(t1) FROM tbl1}
} {this program is free software}

do_test func-4.5 {
  catchsql {SELECT round(a,b,c) FROM t1}
} {1 {wrong number of arguments to function round()}}
do_test func-4.6 {
  catchsql {SELECT round(b,2) FROM t1 ORDER BY b}
} {0 {-2.00 1.23 2.00}}

} {0 {3.0 -12345.68 -5.000}}
do_test func-4.10 {
  catchsql {SELECT 'x' || round(c,a) || 'y' FROM t1 ORDER BY a}
} {0 {x3.0y x-12345.68y x-5.000y}}
do_test func-4.11 {
  catchsql {SELECT round() FROM t1 ORDER BY a}
} {1 {wrong number of arguments to function round()}}
do_test func-4.12 {
  execsql {SELECT round(a,2) FROM t2}
} {1.00 0.00 345.00 0.00 67890.00}
do_test func-4.13 {
  execsql {SELECT round(t1,2) FROM tbl1}
} {0.00 0.00 0.00 0.00 0.00}

# Test the upper() and lower() functions
#
do_test func-5.1 {
  execsql {SELECT upper(t1) FROM tbl1}
} {THIS PROGRAM IS FREE SOFTWARE}
do_test func-5.2 {
  execsql {SELECT lower(upper(t1)) FROM tbl1}
} {this program is free software}
do_test func-5.3 {
  execsql {SELECT upper(a), lower(a) FROM t2}
} {1 1 {} {} 345 345 {} {} 67890 67890}
do_test func-5.4 {
  catchsql {SELECT upper(a,5) FROM t2}
} {1 {wrong number of arguments to function upper()}}
do_test func-5.5 {
  catchsql {SELECT upper(*) FROM t2}
} {1 {wrong number of arguments to function upper()}}

# Test the coalesce() function
#
do_test func-6.1 {
  execsql {SELECT coalesce(a,'xyz') FROM t2}
} {1 xyz 345 xyz 67890}
do_test func-6.2 {
  execsql {SELECT coalesce(upper(a),'nil') FROM t2}
} {1 nil 345 nil 67890}


finish_test

# 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 1.22 2002/03/02 17:04:09 drh Exp $

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

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

           FROM test2, test1}
} {11 2.2}
do_test select1-1.13 {
  execsql {SELECT min(test1.f1,test2.r1), max(test1.f2,test2.r2)
           FROM test1, test2}
} {1.1 22}

set long {This is a string that is too big to fit inside a NBFS buffer}
do_test select1-2.0 {
  execsql "
    DROP TABLE test2;
    DELETE FROM test1;
    INSERT INTO test1 VALUES(11,22);
    INSERT INTO test1 VALUES(33,44);
    CREATE TABLE t3(a,b);
    INSERT INTO t3 VALUES('abc',NULL);
    INSERT INTO t3 VALUES(NULL,'xyz');
    INSERT INTO t3 SELECT * FROM test1;
    CREATE TABLE t4(a,b);
    INSERT INTO t4 VALUES(NULL,'$long');
    SELECT * FROM t3;
  "
} {abc {} {} xyz 11 22 33 44}

# Error messges from sqliteExprCheck
#
do_test select1-2.1 {
  set v [catch {execsql {SELECT count(f1,f2) FROM test1}} msg]
  lappend v $msg
} {1 {wrong number of arguments to function count()}}

  set v [catch {execsql {SELECT COUNT(*) FROM test1}} msg]
  lappend v $msg
} {0 2}
do_test select1-2.5 {
  set v [catch {execsql {SELECT COUNT(*)+1 FROM test1}} msg]
  lappend v $msg
} {0 3}
do_test select1-2.5.1 {
  execsql {SELECT count(*),count(a),count(b) FROM t3}
} {4 3 3}
do_test select1-2.5.2 {
  execsql {SELECT count(*),count(a),count(b) FROM t4}
} {1 0 1}
do_test select1-2.5.3 {
  execsql {SELECT count(*),count(a),count(b) FROM t4 WHERE b=5}
} {0 0 0}
do_test select1-2.6 {
  set v [catch {execsql {SELECT min(*) FROM test1}} msg]
  lappend v $msg
} {1 {wrong number of arguments to function min()}}
do_test select1-2.7 {
  set v [catch {execsql {SELECT Min(f1) FROM test1}} msg]
  lappend v $msg
} {0 11}
do_test select1-2.8 {
  set v [catch {execsql {SELECT MIN(f1,f2) FROM test1}} msg]
  lappend v [lsort $msg]
} {0 {11 33}}
do_test select1-2.8.1 {
  execsql {SELECT coalesce(min(a),'xyzzy') FROM t3}
} {xyzzy}
do_test select1-2.8.2 {
  execsql {SELECT min(coalesce(a,'xyzzy')) FROM t3}
} {11}
do_test select1-2.8.3 {
  execsql {SELECT min(b), min(b) FROM t4}
} [list $long $long]
do_test select1-2.9 {
  set v [catch {execsql {SELECT MAX(*) FROM test1}} msg]
  lappend v $msg
} {1 {wrong number of arguments to function MAX()}}
do_test select1-2.10 {
  set v [catch {execsql {SELECT Max(f1) FROM test1}} msg]
  lappend v $msg
} {0 33}
do_test select1-2.11 {
  set v [catch {execsql {SELECT max(f1,f2) FROM test1}} msg]
  lappend v [lsort $msg]
} {0 {22 44}}
do_test select1-2.12 {
  set v [catch {execsql {SELECT MAX(f1,f2)+1 FROM test1}} msg]
  lappend v [lsort $msg]
} {0 {23 45}}
do_test select1-2.13 {
  set v [catch {execsql {SELECT MAX(f1)+1 FROM test1}} msg]
  lappend v $msg
} {0 34}
do_test select1-2.13.1 {
  execsql {SELECT coalesce(max(a),'xyzzy') FROM t3}
} {abc}
do_test select1-2.13.1 {
  execsql {SELECT max(coalesce(a,'xyzzy')) FROM t3}
} {xyzzy}
do_test select1-2.14 {
  set v [catch {execsql {SELECT SUM(*) FROM test1}} msg]
  lappend v $msg
} {1 {wrong number of arguments to function SUM()}}
do_test select1-2.15 {
  set v [catch {execsql {SELECT Sum(f1) FROM test1}} msg]
  lappend v $msg
} {0 44}
do_test select1-2.16 {
  set v [catch {execsql {SELECT sum(f1,f2) FROM test1}} msg]
  lappend v $msg
} {1 {wrong number of arguments to function sum()}}
do_test select1-2.17 {
  set v [catch {execsql {SELECT SUM(f1)+1 FROM test1}} msg]
  lappend v $msg
} {0 45}
do_test select1-2.17.1 {
  execsql {SELECT sum(a) FROM t3}
} {44}
do_test select1-2.18 {
  set v [catch {execsql {SELECT XYZZY(f1) FROM test1}} msg]
  lappend v $msg
} {1 {no such function: XYZZY}}
do_test select1-2.19 {
  set v [catch {execsql {SELECT SUM(min(f1,f2)) FROM test1}} msg]
  lappend v $msg

    clause is handled as a special case which avoids a complete table scan.</li>
<li>Automatically generated ROWIDs are now sequential.</li>
<li>Do not allow dot-commands of the command-line shell to occur in the
    middle of a real SQL command.</li>
<li>Modifications to the "lemon" parser generator so that the parser tables
    are 4 times smaller.</li>
<li>Added support for user-defined functions implemented in C.</li>
<li>Added support for VIEWs.</li>
<li>Added the subquery flattening optimizer.</li>
}

chng {2002 Feb 18 (2.3.3)} {
<li>Allow identifiers to be quoted in square brackets, for compatibility
    with MS-Access.</li>
<li>Added support for sub-queries in the FROM clause of a SELECT.</li>
<li>More efficient implementation of sqliteFileExists() under Windows.