**    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 contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.65 2008/01/03 00:01:24 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_ATTACH
/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple
................................................................................
      SQLITE_OK!=(rc = resolveAttachExpr(&sName, pKey))
  ){
    pParse->nErr++;
    goto attach_end;
  }

  v = sqlite3GetVdbe(pParse);
  sqlite3ExprCode(pParse, pFilename);
  sqlite3ExprCode(pParse, pDbname);
  sqlite3ExprCode(pParse, pKey);

  assert( v || db->mallocFailed );
  if( v ){
    sqlite3VdbeAddOp2(v, OP_Function, 0, nFunc);
    pFunc = sqlite3FindFunction(db, zFunc, strlen(zFunc), nFunc, SQLITE_UTF8,0);
    sqlite3VdbeChangeP4(v, -1, (char *)pFunc, P4_FUNCDEF);

**    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 contains code used to implement the ATTACH and DETACH commands.
**
** $Id: attach.c,v 1.66 2008/01/03 23:44:53 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_ATTACH
/*
** Resolve an expression that was part of an ATTACH or DETACH statement. This
** is slightly different from resolving a normal SQL expression, because simple
................................................................................
      SQLITE_OK!=(rc = resolveAttachExpr(&sName, pKey))
  ){
    pParse->nErr++;
    goto attach_end;
  }

  v = sqlite3GetVdbe(pParse);
  sqlite3ExprCode(pParse, pFilename, 0);
  sqlite3ExprCode(pParse, pDbname, 0);
  sqlite3ExprCode(pParse, pKey, 0);

  assert( v || db->mallocFailed );
  if( v ){
    sqlite3VdbeAddOp2(v, OP_Function, 0, nFunc);
    pFunc = sqlite3FindFunction(db, zFunc, strlen(zFunc), nFunc, SQLITE_UTF8,0);
    sqlite3VdbeChangeP4(v, -1, (char *)pFunc, P4_FUNCDEF);

**    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 1.328 2008/01/03 18:44:59 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
          */
          if( testAddr>0 && !sqlite3ExprIsConstant(pE2) ){
            sqlite3VdbeChangeToNoop(v, testAddr-1, 3);
            testAddr = 0;
          }

          /* Evaluate the expression and insert it into the temp table */
          sqlite3ExprCode(pParse, pE2);
          sqlite3VdbeAddOp4(v, OP_MakeRecord, 1, 0, 0, &affinity, 1);
          sqlite3VdbeAddOp1(v, OP_IdxInsert, pExpr->iTable);
        }
      }
      sqlite3VdbeChangeP4(v, addr, (void *)&keyInfo, P4_KEYINFO);
      break;
    }
................................................................................
    }
#endif
  }
}

/*
** Generate code into the current Vdbe to evaluate the given
** expression and leave the result on the top of stack.





**
** This code depends on the fact that certain token values (ex: TK_EQ)
** are the same as opcode values (ex: OP_Eq) that implement the corresponding
** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
** the make process cause these values to align.  Assert()s in the code
** below verify that the numbers are aligned correctly.
*/
void sqlite3ExprCode(Parse *pParse, Expr *pExpr){
  Vdbe *v = pParse->pVdbe;
  int op;

  int stackChng = 1;    /* Amount of change to stack depth */



  if( v==0 ) return;
  if( pExpr==0 ){
    sqlite3VdbeAddOp0(v, OP_Null);
    return;





  }




  op = pExpr->op;

  switch( op ){
    case TK_AGG_COLUMN: {
      AggInfo *pAggInfo = pExpr->pAggInfo;
      struct AggInfo_col *pCol = &pAggInfo->aCol[pExpr->iAgg];
      if( !pAggInfo->directMode ){
        sqlite3VdbeAddOp1(v, OP_MemLoad, pCol->iMem);
        break;
      }else if( pAggInfo->useSortingIdx ){
        sqlite3VdbeAddOp2(v, OP_Column, pAggInfo->sortingIdx,
                              pCol->iSorterColumn);

        break;
      }
      /* Otherwise, fall thru into the TK_COLUMN case */
    }
    case TK_COLUMN: {
      if( pExpr->iTable<0 ){
        /* This only happens when coding check constraints */
        assert( pParse->ckOffset>0 );
        sqlite3VdbeAddOp2(v, OP_Dup, pParse->ckOffset-pExpr->iColumn-1, 1);
      }else{
        sqlite3ExprCodeGetColumn(v, pExpr->pTab,
                                 pExpr->iColumn, pExpr->iTable, 0);

      }
      break;
    }
    case TK_INTEGER: {
      codeInteger(v, (char*)pExpr->token.z, pExpr->token.n, 0);
      break;
    }
................................................................................
      sqlite3VdbeAddOp1(v, OP_MemLoad, pExpr->iTable);
      break;
    }
#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */
      int aff, to_op;
      sqlite3ExprCode(pParse, pExpr->pLeft);
      aff = sqlite3AffinityType(&pExpr->token);
      to_op = aff - SQLITE_AFF_TEXT + OP_ToText;
      assert( to_op==OP_ToText    || aff!=SQLITE_AFF_TEXT    );
      assert( to_op==OP_ToBlob    || aff!=SQLITE_AFF_NONE    );
      assert( to_op==OP_ToNumeric || aff!=SQLITE_AFF_NUMERIC );
      assert( to_op==OP_ToInt     || aff!=SQLITE_AFF_INTEGER );
      assert( to_op==OP_ToReal    || aff!=SQLITE_AFF_REAL    );
................................................................................
    case TK_EQ: {
      assert( TK_LT==OP_Lt );
      assert( TK_LE==OP_Le );
      assert( TK_GT==OP_Gt );
      assert( TK_GE==OP_Ge );
      assert( TK_EQ==OP_Eq );
      assert( TK_NE==OP_Ne );
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3ExprCode(pParse, pExpr->pRight);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, 0, 0);
      stackChng = -1;
      break;
    }
    case TK_AND:
    case TK_OR:
    case TK_PLUS:
................................................................................
      assert( TK_REM==OP_Remainder );
      assert( TK_BITAND==OP_BitAnd );
      assert( TK_BITOR==OP_BitOr );
      assert( TK_SLASH==OP_Divide );
      assert( TK_LSHIFT==OP_ShiftLeft );
      assert( TK_RSHIFT==OP_ShiftRight );
      assert( TK_CONCAT==OP_Concat );
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3ExprCode(pParse, pExpr->pRight);
      sqlite3VdbeAddOp0(v, op);
      stackChng = -1;
      break;
    }
    case TK_UMINUS: {
      Expr *pLeft = pExpr->pLeft;
      assert( pLeft );
................................................................................
      }
      /* Fall through into TK_NOT */
    }
    case TK_BITNOT:
    case TK_NOT: {
      assert( TK_BITNOT==OP_BitNot );
      assert( TK_NOT==OP_Not );
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3VdbeAddOp0(v, op);
      stackChng = 0;
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      int dest;
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      sqlite3VdbeAddOp1(v, OP_Integer, 1);
      sqlite3ExprCode(pParse, pExpr->pLeft);
      dest = sqlite3VdbeCurrentAddr(v) + 2;
      sqlite3VdbeAddOp2(v, op, 1, dest);
      sqlite3VdbeAddOp1(v, OP_AddImm, -1);
      stackChng = 0;
      break;
    }
    case TK_AGG_FUNCTION: {
................................................................................
      u8 enc = ENC(db);
      CollSeq *pColl = 0;

      zId = (char*)pExpr->token.z;
      nId = pExpr->token.n;
      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
      assert( pDef!=0 );
      nExpr = sqlite3ExprCodeExprList(pParse, pList);
#ifndef SQLITE_OMIT_VIRTUALTABLE
      /* Possibly overload the function if the first argument is
      ** a virtual table column.
      **
      ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
      ** second argument, not the first, as the argument to test to
      ** see if it is a column in a virtual table.  This is done because
................................................................................

      sqlite3VdbeAddOp1(v, OP_Integer, 1);
      pParse->ckOffset = (ckOffset ? (ckOffset+1) : 0);

      /* Code the <expr> from "<expr> IN (...)". The temporary table
      ** pExpr->iTable contains the values that make up the (...) set.
      */
      sqlite3ExprCode(pParse, pExpr->pLeft);
      addr = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp2(v, OP_NotNull, -1, addr+4);            /* addr + 0 */
      sqlite3VdbeAddOp1(v, OP_Pop, 2);
      sqlite3VdbeAddOp0(v, OP_Null);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, iLabel);
      if( eType==IN_INDEX_ROWID ){
        int iAddr = sqlite3VdbeCurrentAddr(v)+3;
................................................................................
      break;
    }
#endif
    case TK_BETWEEN: {
      Expr *pLeft = pExpr->pLeft;
      struct ExprList_item *pLItem = pExpr->pList->a;
      Expr *pRight = pLItem->pExpr;
      sqlite3ExprCode(pParse, pLeft);
      sqlite3VdbeAddOp0(v, OP_Dup);
      sqlite3ExprCode(pParse, pRight);
      codeCompare(pParse, pLeft, pRight, OP_Ge, 0, 0);
      sqlite3VdbeAddOp1(v, OP_Pull, 1);
      pLItem++;
      pRight = pLItem->pExpr;
      sqlite3ExprCode(pParse, pRight);
      codeCompare(pParse, pLeft, pRight, OP_Le, 0, 0);
      sqlite3VdbeAddOp0(v, OP_And);
      break;
    }
    case TK_UPLUS: {
      sqlite3ExprCode(pParse, pExpr->pLeft);
      stackChng = 0;
      break;
    }
    case TK_CASE: {
      int expr_end_label;
      int jumpInst;
      int nExpr;
................................................................................
      assert((pExpr->pList->nExpr % 2) == 0);
      assert(pExpr->pList->nExpr > 0);
      pEList = pExpr->pList;
      aListelem = pEList->a;
      nExpr = pEList->nExpr;
      expr_end_label = sqlite3VdbeMakeLabel(v);
      if( pExpr->pLeft ){
        sqlite3ExprCode(pParse, pExpr->pLeft);
      }
      for(i=0; i<nExpr; i=i+2){
        sqlite3ExprCode(pParse, aListelem[i].pExpr);
        if( pExpr->pLeft ){
          sqlite3VdbeAddOp2(v, OP_Dup, 1, 1);
          jumpInst = codeCompare(pParse, pExpr->pLeft, aListelem[i].pExpr,
                                 OP_Ne, 0, 1);
          sqlite3VdbeAddOp1(v, OP_Pop, 1);
        }else{
          jumpInst = sqlite3VdbeAddOp2(v, OP_IfNot, 1, 0);
        }
        sqlite3ExprCode(pParse, aListelem[i+1].pExpr);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, expr_end_label);
        sqlite3VdbeJumpHere(v, jumpInst);
      }
      if( pExpr->pLeft ){
        sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      }
      if( pExpr->pRight ){
        sqlite3ExprCode(pParse, pExpr->pRight);
      }else{
        sqlite3VdbeAddOp2(v, OP_Null, 0, 0);
      }
      sqlite3VdbeResolveLabel(v, expr_end_label);
      break;
    }
#ifndef SQLITE_OMIT_TRIGGER
    case TK_RAISE: {
      if( !pParse->trigStack ){
        sqlite3ErrorMsg(pParse,
                       "RAISE() may only be used within a trigger-program");
        return;
      }
      if( pExpr->iColumn!=OE_Ignore ){
         assert( pExpr->iColumn==OE_Rollback ||
                 pExpr->iColumn == OE_Abort ||
                 pExpr->iColumn == OE_Fail );
         sqlite3DequoteExpr(pParse->db, pExpr);
         sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, pExpr->iColumn, 0,
................................................................................
         VdbeComment((v, "raise(IGNORE)"));
      }
      stackChng = 0;
      break;
    }
#endif
  }




  if( pParse->ckOffset ){
    pParse->ckOffset += stackChng;
    assert( pParse->ckOffset );
  }

}

#ifndef SQLITE_OMIT_TRIGGER
/*
** Generate code that evalutes the given expression and leaves the result
** on the stack.  See also sqlite3ExprCode().
**
................................................................................
void sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr){
  Vdbe *v = pParse->pVdbe;
  VdbeOp *pOp;
  int iMem;
  int addr1, addr2;
  if( v==0 ) return;
  addr1 = sqlite3VdbeCurrentAddr(v);
  sqlite3ExprCode(pParse, pExpr);
  addr2 = sqlite3VdbeCurrentAddr(v);
  if( addr2>addr1+1
   || ((pOp = sqlite3VdbeGetOp(v, addr1))!=0 && pOp->opcode==OP_Function) ){
    iMem = pExpr->iTable = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_MemStore, iMem, 0);
    pExpr->op = TK_REGISTER;
  }
}
#endif

/*
** Generate code to evaluate an expression and store the result in
** a designated register.  If the target register number is negative,
** allocate a new register to store the result.  Return the target
** register number regardless.
**
** The current implementation is a rough prototype for experimental
** purposes.  There are many optimization opportunities here.
*/
int sqlite3ExprIntoReg(Parse *pParse, Expr *pExpr, int target){
  Vdbe *v = pParse->pVdbe;
  assert( v!=0 || pParse->db->mallocFailed );
  assert( pExpr!=0 || pParse->db->mallocFailed );
  if( v==0 || pExpr==0 ) return -1;
  if( target<=0 ){
    target = ++pParse->nMem;
  }
  if( pExpr->op==TK_COLUMN && pExpr->iTable>=0 ){
    sqlite3ExprCodeGetColumn(v, pExpr->pTab,
                             pExpr->iColumn, pExpr->iTable, target);
  }else{
    sqlite3ExprCode(pParse, pExpr);
    sqlite3VdbeAddOp2(v, OP_MemStore, target, 1);
  }
  return target;
}

/*
** Generate code that pushes the value of every element of the given
** expression list onto the stack.
**
** Return the number of elements pushed onto the stack.
*/
int sqlite3ExprCodeExprList(
  Parse *pParse,     /* Parsing context */
  ExprList *pList    /* The expression list to be coded */

){
  struct ExprList_item *pItem;
  int i, n;
  if( pList==0 ) return 0;
  n = pList->nExpr;






  for(pItem=pList->a, i=n; i>0; i--, pItem++){
    sqlite3ExprCode(pParse, pItem->pExpr);

  }
  return n;
}

/*
** Generate code for a boolean expression such that a jump is made
** to the label "dest" if the expression is true but execution
................................................................................
    case TK_EQ: {
      assert( TK_LT==OP_Lt );
      assert( TK_LE==OP_Le );
      assert( TK_GT==OP_Gt );
      assert( TK_GE==OP_Ge );
      assert( TK_EQ==OP_Eq );
      assert( TK_NE==OP_Ne );
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3ExprCode(pParse, pExpr->pRight);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3VdbeAddOp2(v, op, 1, dest);
      break;
    }
    case TK_BETWEEN: {
      /* The expression "x BETWEEN y AND z" is implemented as:
      **
      ** 1 IF (x < y) GOTO 3
      ** 2 IF (x <= z) GOTO <dest>
      ** 3 ...
      */
      int addr;
      Expr *pLeft = pExpr->pLeft;
      Expr *pRight = pExpr->pList->a[0].pExpr;
      sqlite3ExprCode(pParse, pLeft);
      sqlite3VdbeAddOp2(v, OP_Dup, 0, 0);
      sqlite3ExprCode(pParse, pRight);
      addr = codeCompare(pParse, pLeft, pRight, OP_Lt, 0, !jumpIfNull);

      pRight = pExpr->pList->a[1].pExpr;
      sqlite3ExprCode(pParse, pRight);
      codeCompare(pParse, pLeft, pRight, OP_Le, dest, jumpIfNull);

      sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
      sqlite3VdbeJumpHere(v, addr);
      sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      break;
    }
    default: {
      sqlite3ExprCode(pParse, pExpr);
      sqlite3VdbeAddOp2(v, OP_If, jumpIfNull, dest);
      break;
    }
  }
  pParse->ckOffset = ckOffset;
}

................................................................................
    }
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3ExprCode(pParse, pExpr->pRight);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      sqlite3ExprCode(pParse, pExpr->pLeft);
      sqlite3VdbeAddOp2(v, op, 1, dest);
      break;
    }
    case TK_BETWEEN: {
      /* The expression is "x BETWEEN y AND z". It is implemented as:
      **
      ** 1 IF (x >= y) GOTO 3
      ** 2 GOTO <dest>
      ** 3 IF (x > z) GOTO <dest>
      */
      int addr;
      Expr *pLeft = pExpr->pLeft;
      Expr *pRight = pExpr->pList->a[0].pExpr;
      sqlite3ExprCode(pParse, pLeft);
      sqlite3VdbeAddOp2(v, OP_Dup, 0, 0);
      sqlite3ExprCode(pParse, pRight);
      addr = sqlite3VdbeCurrentAddr(v);
      codeCompare(pParse, pLeft, pRight, OP_Ge, addr+3, !jumpIfNull);

      sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, dest);
      pRight = pExpr->pList->a[1].pExpr;
      sqlite3ExprCode(pParse, pRight);
      codeCompare(pParse, pLeft, pRight, OP_Gt, dest, jumpIfNull);
      break;
    }
    default: {
      sqlite3ExprCode(pParse, pExpr);
      sqlite3VdbeAddOp2(v, OP_IfNot, jumpIfNull, dest);
      break;
    }
  }
  pParse->ckOffset = ckOffset;
}

**    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 1.329 2008/01/03 23:44:53 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**
................................................................................
          */
          if( testAddr>0 && !sqlite3ExprIsConstant(pE2) ){
            sqlite3VdbeChangeToNoop(v, testAddr-1, 3);
            testAddr = 0;
          }

          /* Evaluate the expression and insert it into the temp table */
          sqlite3ExprCode(pParse, pE2, 0);
          sqlite3VdbeAddOp4(v, OP_MakeRecord, 1, 0, 0, &affinity, 1);
          sqlite3VdbeAddOp1(v, OP_IdxInsert, pExpr->iTable);
        }
      }
      sqlite3VdbeChangeP4(v, addr, (void *)&keyInfo, P4_KEYINFO);
      break;
    }
................................................................................
    }
#endif
  }
}

/*
** Generate code into the current Vdbe to evaluate the given
** expression and leaves the result in a register on on the stack.
**
** If the target register number is negative, allocate a new
** register to store the result.  If the target register number
** is zero then push the result onto the stack.  Return the target
** register number regardless.
**
** This code depends on the fact that certain token values (ex: TK_EQ)
** are the same as opcode values (ex: OP_Eq) that implement the corresponding
** operation.  Special comments in vdbe.c and the mkopcodeh.awk script in
** the make process cause these values to align.  Assert()s in the code
** below verify that the numbers are aligned correctly.
*/
int sqlite3ExprCode(Parse *pParse, Expr *pExpr, int target){
  Vdbe *v = pParse->pVdbe;
  int op;
  int inReg = 0;
  int stackChng = 0;
  int subtarget = -1;

  assert( v!=0 || pParse->db->mallocFailed );
  if( v==0 ) return 0;



  if( target<0 ){
    target = ++pParse->nMem;
  }else if( target==0 ){
    stackChng = 1;
    subtarget = 0;
  }

  if( pExpr==0 ){
    op = TK_NULL;
  }else{
    op = pExpr->op;
  }
  switch( op ){
    case TK_AGG_COLUMN: {
      AggInfo *pAggInfo = pExpr->pAggInfo;
      struct AggInfo_col *pCol = &pAggInfo->aCol[pExpr->iAgg];
      if( !pAggInfo->directMode ){
        sqlite3VdbeAddOp1(v, OP_MemLoad, pCol->iMem);
        break;
      }else if( pAggInfo->useSortingIdx ){
        sqlite3VdbeAddOp3(v, OP_Column, pAggInfo->sortingIdx,
                              pCol->iSorterColumn, target);
        inReg = 1;
        break;
      }
      /* Otherwise, fall thru into the TK_COLUMN case */
    }
    case TK_COLUMN: {
      if( pExpr->iTable<0 ){
        /* This only happens when coding check constraints */
        assert( pParse->ckOffset>0 );
        sqlite3VdbeAddOp2(v, OP_Dup, pParse->ckOffset-pExpr->iColumn-1, 1);
      }else{
        sqlite3ExprCodeGetColumn(v, pExpr->pTab,
                                 pExpr->iColumn, pExpr->iTable, target);
        inReg = 1;
      }
      break;
    }
    case TK_INTEGER: {
      codeInteger(v, (char*)pExpr->token.z, pExpr->token.n, 0);
      break;
    }
................................................................................
      sqlite3VdbeAddOp1(v, OP_MemLoad, pExpr->iTable);
      break;
    }
#ifndef SQLITE_OMIT_CAST
    case TK_CAST: {
      /* Expressions of the form:   CAST(pLeft AS token) */
      int aff, to_op;
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      aff = sqlite3AffinityType(&pExpr->token);
      to_op = aff - SQLITE_AFF_TEXT + OP_ToText;
      assert( to_op==OP_ToText    || aff!=SQLITE_AFF_TEXT    );
      assert( to_op==OP_ToBlob    || aff!=SQLITE_AFF_NONE    );
      assert( to_op==OP_ToNumeric || aff!=SQLITE_AFF_NUMERIC );
      assert( to_op==OP_ToInt     || aff!=SQLITE_AFF_INTEGER );
      assert( to_op==OP_ToReal    || aff!=SQLITE_AFF_REAL    );
................................................................................
    case TK_EQ: {
      assert( TK_LT==OP_Lt );
      assert( TK_LE==OP_Le );
      assert( TK_GT==OP_Gt );
      assert( TK_GE==OP_Ge );
      assert( TK_EQ==OP_Eq );
      assert( TK_NE==OP_Ne );
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3ExprCode(pParse, pExpr->pRight, 0);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, 0, 0);
      stackChng = -1;
      break;
    }
    case TK_AND:
    case TK_OR:
    case TK_PLUS:
................................................................................
      assert( TK_REM==OP_Remainder );
      assert( TK_BITAND==OP_BitAnd );
      assert( TK_BITOR==OP_BitOr );
      assert( TK_SLASH==OP_Divide );
      assert( TK_LSHIFT==OP_ShiftLeft );
      assert( TK_RSHIFT==OP_ShiftRight );
      assert( TK_CONCAT==OP_Concat );
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3ExprCode(pParse, pExpr->pRight, 0);
      sqlite3VdbeAddOp0(v, op);
      stackChng = -1;
      break;
    }
    case TK_UMINUS: {
      Expr *pLeft = pExpr->pLeft;
      assert( pLeft );
................................................................................
      }
      /* Fall through into TK_NOT */
    }
    case TK_BITNOT:
    case TK_NOT: {
      assert( TK_BITNOT==OP_BitNot );
      assert( TK_NOT==OP_Not );
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3VdbeAddOp0(v, op);
      stackChng = 0;
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      int dest;
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      sqlite3VdbeAddOp1(v, OP_Integer, 1);
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      dest = sqlite3VdbeCurrentAddr(v) + 2;
      sqlite3VdbeAddOp2(v, op, 1, dest);
      sqlite3VdbeAddOp1(v, OP_AddImm, -1);
      stackChng = 0;
      break;
    }
    case TK_AGG_FUNCTION: {
................................................................................
      u8 enc = ENC(db);
      CollSeq *pColl = 0;

      zId = (char*)pExpr->token.z;
      nId = pExpr->token.n;
      pDef = sqlite3FindFunction(pParse->db, zId, nId, nExpr, enc, 0);
      assert( pDef!=0 );
      nExpr = sqlite3ExprCodeExprList(pParse, pList, 0);
#ifndef SQLITE_OMIT_VIRTUALTABLE
      /* Possibly overload the function if the first argument is
      ** a virtual table column.
      **
      ** For infix functions (LIKE, GLOB, REGEXP, and MATCH) use the
      ** second argument, not the first, as the argument to test to
      ** see if it is a column in a virtual table.  This is done because
................................................................................

      sqlite3VdbeAddOp1(v, OP_Integer, 1);
      pParse->ckOffset = (ckOffset ? (ckOffset+1) : 0);

      /* Code the <expr> from "<expr> IN (...)". The temporary table
      ** pExpr->iTable contains the values that make up the (...) set.
      */
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      addr = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp2(v, OP_NotNull, -1, addr+4);            /* addr + 0 */
      sqlite3VdbeAddOp1(v, OP_Pop, 2);
      sqlite3VdbeAddOp0(v, OP_Null);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, iLabel);
      if( eType==IN_INDEX_ROWID ){
        int iAddr = sqlite3VdbeCurrentAddr(v)+3;
................................................................................
      break;
    }
#endif
    case TK_BETWEEN: {
      Expr *pLeft = pExpr->pLeft;
      struct ExprList_item *pLItem = pExpr->pList->a;
      Expr *pRight = pLItem->pExpr;
      sqlite3ExprCode(pParse, pLeft, 0);
      sqlite3VdbeAddOp0(v, OP_Dup);
      sqlite3ExprCode(pParse, pRight, 0);
      codeCompare(pParse, pLeft, pRight, OP_Ge, 0, 0);
      sqlite3VdbeAddOp1(v, OP_Pull, 1);
      pLItem++;
      pRight = pLItem->pExpr;
      sqlite3ExprCode(pParse, pRight, 0);
      codeCompare(pParse, pLeft, pRight, OP_Le, 0, 0);
      sqlite3VdbeAddOp0(v, OP_And);
      break;
    }
    case TK_UPLUS: {
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      stackChng = 0;
      break;
    }
    case TK_CASE: {
      int expr_end_label;
      int jumpInst;
      int nExpr;
................................................................................
      assert((pExpr->pList->nExpr % 2) == 0);
      assert(pExpr->pList->nExpr > 0);
      pEList = pExpr->pList;
      aListelem = pEList->a;
      nExpr = pEList->nExpr;
      expr_end_label = sqlite3VdbeMakeLabel(v);
      if( pExpr->pLeft ){
        sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      }
      for(i=0; i<nExpr; i=i+2){
        sqlite3ExprCode(pParse, aListelem[i].pExpr, 0);
        if( pExpr->pLeft ){
          sqlite3VdbeAddOp2(v, OP_Dup, 1, 1);
          jumpInst = codeCompare(pParse, pExpr->pLeft, aListelem[i].pExpr,
                                 OP_Ne, 0, 1);
          sqlite3VdbeAddOp1(v, OP_Pop, 1);
        }else{
          jumpInst = sqlite3VdbeAddOp2(v, OP_IfNot, 1, 0);
        }
        sqlite3ExprCode(pParse, aListelem[i+1].pExpr, 0);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, expr_end_label);
        sqlite3VdbeJumpHere(v, jumpInst);
      }
      if( pExpr->pLeft ){
        sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      }
      if( pExpr->pRight ){
        sqlite3ExprCode(pParse, pExpr->pRight, 0);
      }else{
        sqlite3VdbeAddOp2(v, OP_Null, 0, 0);
      }
      sqlite3VdbeResolveLabel(v, expr_end_label);
      break;
    }
#ifndef SQLITE_OMIT_TRIGGER
    case TK_RAISE: {
      if( !pParse->trigStack ){
        sqlite3ErrorMsg(pParse,
                       "RAISE() may only be used within a trigger-program");
        return 0;
      }
      if( pExpr->iColumn!=OE_Ignore ){
         assert( pExpr->iColumn==OE_Rollback ||
                 pExpr->iColumn == OE_Abort ||
                 pExpr->iColumn == OE_Fail );
         sqlite3DequoteExpr(pParse->db, pExpr);
         sqlite3VdbeAddOp4(v, OP_Halt, SQLITE_CONSTRAINT, pExpr->iColumn, 0,
................................................................................
         VdbeComment((v, "raise(IGNORE)"));
      }
      stackChng = 0;
      break;
    }
#endif
  }
  if( target && !inReg ){
    sqlite3VdbeAddOp2(v, OP_MemStore, target, 1);
    stackChng = 0;
  }
  if( pParse->ckOffset ){
    pParse->ckOffset += stackChng;
    assert( pParse->ckOffset );
  }
  return target;
}

#ifndef SQLITE_OMIT_TRIGGER
/*
** Generate code that evalutes the given expression and leaves the result
** on the stack.  See also sqlite3ExprCode().
**
................................................................................
void sqlite3ExprCodeAndCache(Parse *pParse, Expr *pExpr){
  Vdbe *v = pParse->pVdbe;
  VdbeOp *pOp;
  int iMem;
  int addr1, addr2;
  if( v==0 ) return;
  addr1 = sqlite3VdbeCurrentAddr(v);
  sqlite3ExprCode(pParse, pExpr, 0);
  addr2 = sqlite3VdbeCurrentAddr(v);
  if( addr2>addr1+1
   || ((pOp = sqlite3VdbeGetOp(v, addr1))!=0 && pOp->opcode==OP_Function) ){
    iMem = pExpr->iTable = ++pParse->nMem;
    sqlite3VdbeAddOp2(v, OP_MemStore, iMem, 0);
    pExpr->op = TK_REGISTER;
  }
}
#endif




























/*
** Generate code that pushes the value of every element of the given
** expression list onto the stack.
**
** Return the number of elements pushed onto the stack.
*/
int sqlite3ExprCodeExprList(
  Parse *pParse,     /* Parsing context */
  ExprList *pList,   /* The expression list to be coded */
  int target         /* Where to write results */
){
  struct ExprList_item *pItem;
  int i, n, incr = 1;
  if( pList==0 ) return 0;
  n = pList->nExpr;
  if( target<0 ){
    target = pParse->nMem+1;
    pParse->nMem += n;
  }else if( target==0 ){
    incr = 0;
  }
  for(pItem=pList->a, i=n; i>0; i--, pItem++){
    sqlite3ExprCode(pParse, pItem->pExpr, target);
    target += incr; 
  }
  return n;
}

/*
** Generate code for a boolean expression such that a jump is made
** to the label "dest" if the expression is true but execution
................................................................................
    case TK_EQ: {
      assert( TK_LT==OP_Lt );
      assert( TK_LE==OP_Le );
      assert( TK_GT==OP_Gt );
      assert( TK_GE==OP_Ge );
      assert( TK_EQ==OP_Eq );
      assert( TK_NE==OP_Ne );
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3ExprCode(pParse, pExpr->pRight, 0);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      assert( TK_ISNULL==OP_IsNull );
      assert( TK_NOTNULL==OP_NotNull );
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3VdbeAddOp2(v, op, 1, dest);
      break;
    }
    case TK_BETWEEN: {
      /* The expression "x BETWEEN y AND z" is implemented as:
      **
      ** 1 IF (x < y) GOTO 3
      ** 2 IF (x <= z) GOTO <dest>
      ** 3 ...
      */
      int addr;
      Expr *pLeft = pExpr->pLeft;
      Expr *pRight = pExpr->pList->a[0].pExpr;
      sqlite3ExprCode(pParse, pLeft, 0);
      sqlite3VdbeAddOp2(v, OP_Dup, 0, 0);
      sqlite3ExprCode(pParse, pRight, 0);
      addr = codeCompare(pParse, pLeft, pRight, OP_Lt, 0, !jumpIfNull);

      pRight = pExpr->pList->a[1].pExpr;
      sqlite3ExprCode(pParse, pRight, 0);
      codeCompare(pParse, pLeft, pRight, OP_Le, dest, jumpIfNull);

      sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
      sqlite3VdbeJumpHere(v, addr);
      sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      break;
    }
    default: {
      sqlite3ExprCode(pParse, pExpr, 0);
      sqlite3VdbeAddOp2(v, OP_If, jumpIfNull, dest);
      break;
    }
  }
  pParse->ckOffset = ckOffset;
}

................................................................................
    }
    case TK_LT:
    case TK_LE:
    case TK_GT:
    case TK_GE:
    case TK_NE:
    case TK_EQ: {
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3ExprCode(pParse, pExpr->pRight, 0);
      codeCompare(pParse, pExpr->pLeft, pExpr->pRight, op, dest, jumpIfNull);
      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      sqlite3ExprCode(pParse, pExpr->pLeft, 0);
      sqlite3VdbeAddOp2(v, op, 1, dest);
      break;
    }
    case TK_BETWEEN: {
      /* The expression is "x BETWEEN y AND z". It is implemented as:
      **
      ** 1 IF (x >= y) GOTO 3
      ** 2 GOTO <dest>
      ** 3 IF (x > z) GOTO <dest>
      */
      int addr;
      Expr *pLeft = pExpr->pLeft;
      Expr *pRight = pExpr->pList->a[0].pExpr;
      sqlite3ExprCode(pParse, pLeft, 0);
      sqlite3VdbeAddOp2(v, OP_Dup, 0, 0);
      sqlite3ExprCode(pParse, pRight, 0);
      addr = sqlite3VdbeCurrentAddr(v);
      codeCompare(pParse, pLeft, pRight, OP_Ge, addr+3, !jumpIfNull);

      sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      sqlite3VdbeAddOp2(v, OP_Goto, 0, dest);
      pRight = pExpr->pList->a[1].pExpr;
      sqlite3ExprCode(pParse, pRight, 0);
      codeCompare(pParse, pLeft, pRight, OP_Gt, dest, jumpIfNull);
      break;
    }
    default: {
      sqlite3ExprCode(pParse, pExpr, 0);
      sqlite3VdbeAddOp2(v, OP_IfNot, jumpIfNull, dest);
      break;
    }
  }
  pParse->ckOffset = ckOffset;
}

**    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 1.207 2008/01/03 18:03:09 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:
................................................................................
    */
    if( keyColumn<0 ){
      sqlite3VdbeAddOp2(v, OP_Integer, -1, 0);
    }else if( useTempTable ){
      sqlite3VdbeAddOp2(v, OP_Column, srcTab, keyColumn);
    }else{
      assert( pSelect==0 );  /* Otherwise useTempTable is true */
      sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr);
      sqlite3VdbeAddOp2(v, OP_NotNull, -1, sqlite3VdbeCurrentAddr(v)+3);
      sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      sqlite3VdbeAddOp2(v, OP_Integer, -1, 0);
      sqlite3VdbeAddOp2(v, OP_MustBeInt, 0, 0);
    }

    /* Cannot have triggers on a virtual table. If it were possible,
................................................................................
        j = i;
      }else{
        for(j=0; j<pColumn->nId; j++){
          if( pColumn->a[j].idx==i ) break;
        }
      }
      if( pColumn && j>=pColumn->nId ){
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt);
      }else if( useTempTable ){
        sqlite3VdbeAddOp2(v, OP_Column, srcTab, j); 
      }else{
        assert( pSelect==0 ); /* Otherwise useTempTable is true */
        sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr);
      }
    }
................................................................................
    if( keyColumn>=0 ){
      if( useTempTable ){
        sqlite3VdbeAddOp2(v, OP_Column, srcTab, keyColumn);
      }else if( pSelect ){
        sqlite3VdbeAddOp2(v, OP_Dup, nColumn - keyColumn - 1, 1);
      }else{
        VdbeOp *pOp;
        sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr);
        pOp = sqlite3VdbeGetOp(v, sqlite3VdbeCurrentAddr(v) - 1);
        if( pOp && pOp->opcode==OP_Null ){
          appendFlag = 1;
          pOp->opcode = OP_NewRowid;
          pOp->p1 = base;
          pOp->p2 = counterMem;
        }
................................................................................
        }
      }else{
        for(j=0; j<pColumn->nId; j++){
          if( pColumn->a[j].idx==i ) break;
        }
      }
      if( j<0 || nColumn==0 || (pColumn && j>=pColumn->nId) ){
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt);
      }else if( useTempTable ){
        sqlite3VdbeAddOp2(v, OP_Column, srcTab, j); 
      }else if( pSelect ){
        sqlite3VdbeAddOp2(v, OP_Dup, i+nColumn-j+IsVirtual(pTab), 1);
      }else{
        sqlite3ExprCode(pParse, pList->a[j].pExpr);
      }
    }

    /* Generate code to check constraints and generate index keys and
    ** do the insertion.
    */
#ifndef SQLITE_OMIT_VIRTUALTABLE
................................................................................
      }
      case OE_Ignore: {
        sqlite3VdbeAddOp2(v, OP_Pop, nCol+1+hasTwoRowids, 0);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt);
        sqlite3VdbeAddOp2(v, OP_Push, nCol-i, 0);
        break;
      }
    }
    sqlite3VdbeJumpHere(v, addr);
  }

**    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 1.208 2008/01/03 23:44:53 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:
................................................................................
    */
    if( keyColumn<0 ){
      sqlite3VdbeAddOp2(v, OP_Integer, -1, 0);
    }else if( useTempTable ){
      sqlite3VdbeAddOp2(v, OP_Column, srcTab, keyColumn);
    }else{
      assert( pSelect==0 );  /* Otherwise useTempTable is true */
      sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, 0);
      sqlite3VdbeAddOp2(v, OP_NotNull, -1, sqlite3VdbeCurrentAddr(v)+3);
      sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
      sqlite3VdbeAddOp2(v, OP_Integer, -1, 0);
      sqlite3VdbeAddOp2(v, OP_MustBeInt, 0, 0);
    }

    /* Cannot have triggers on a virtual table. If it were possible,
................................................................................
        j = i;
      }else{
        for(j=0; j<pColumn->nId; j++){
          if( pColumn->a[j].idx==i ) break;
        }
      }
      if( pColumn && j>=pColumn->nId ){
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, 0);
      }else if( useTempTable ){
        sqlite3VdbeAddOp2(v, OP_Column, srcTab, j); 
      }else{
        assert( pSelect==0 ); /* Otherwise useTempTable is true */
        sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr);
      }
    }
................................................................................
    if( keyColumn>=0 ){
      if( useTempTable ){
        sqlite3VdbeAddOp2(v, OP_Column, srcTab, keyColumn);
      }else if( pSelect ){
        sqlite3VdbeAddOp2(v, OP_Dup, nColumn - keyColumn - 1, 1);
      }else{
        VdbeOp *pOp;
        sqlite3ExprCode(pParse, pList->a[keyColumn].pExpr, 0);
        pOp = sqlite3VdbeGetOp(v, sqlite3VdbeCurrentAddr(v) - 1);
        if( pOp && pOp->opcode==OP_Null ){
          appendFlag = 1;
          pOp->opcode = OP_NewRowid;
          pOp->p1 = base;
          pOp->p2 = counterMem;
        }
................................................................................
        }
      }else{
        for(j=0; j<pColumn->nId; j++){
          if( pColumn->a[j].idx==i ) break;
        }
      }
      if( j<0 || nColumn==0 || (pColumn && j>=pColumn->nId) ){
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, 0);
      }else if( useTempTable ){
        sqlite3VdbeAddOp2(v, OP_Column, srcTab, j); 
      }else if( pSelect ){
        sqlite3VdbeAddOp2(v, OP_Dup, i+nColumn-j+IsVirtual(pTab), 1);
      }else{
        sqlite3ExprCode(pParse, pList->a[j].pExpr, 0);
      }
    }

    /* Generate code to check constraints and generate index keys and
    ** do the insertion.
    */
#ifndef SQLITE_OMIT_VIRTUALTABLE
................................................................................
      }
      case OE_Ignore: {
        sqlite3VdbeAddOp2(v, OP_Pop, nCol+1+hasTwoRowids, 0);
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
        break;
      }
      case OE_Replace: {
        sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, 0);
        sqlite3VdbeAddOp2(v, OP_Push, nCol-i, 0);
        break;
      }
    }
    sqlite3VdbeJumpHere(v, addr);
  }

**    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 1.382 2008/01/03 18:44:59 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
................................................................................
*/
static void pushOntoSorter(
  Parse *pParse,         /* Parser context */
  ExprList *pOrderBy,    /* The ORDER BY clause */
  Select *pSelect        /* The whole SELECT statement */
){
  Vdbe *v = pParse->pVdbe;
  sqlite3ExprCodeExprList(pParse, pOrderBy);
  sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, 0);
  sqlite3VdbeAddOp2(v, OP_Pull, pOrderBy->nExpr + 1, 0);
  sqlite3VdbeAddOp2(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0);
  sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, 0);
  if( pSelect->iLimit>=0 ){
    int addr1, addr2;
    addr1 = sqlite3VdbeAddOp2(v, OP_IfMemZero, pSelect->iLimit+1, 0);
................................................................................
      sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, iMem+i+1);
    }
  }else if( eDest!=SRT_Exists ){
    /* If the destination is an EXISTS(...) expression, the actual
    ** values returned by the SELECT are not required.
    */
    for(i=0; i<n; i++){
      sqlite3ExprIntoReg(pParse, pEList->a[i].pExpr, iMem+i+1);
    }
  }
  nColumn = n;

  /* If the DISTINCT keyword was present on the SELECT statement
  ** and this row has been seen before, then do not make this row
  ** part of the result.
................................................................................
  ** no rows.
  */
  if( p->pLimit ){
    p->iLimit = iLimit = ++pParse->nMem;
    pParse->nMem++;
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) return;
    sqlite3ExprCode(pParse, p->pLimit);
    sqlite3VdbeAddOp2(v, OP_MustBeInt, 0, 0);
    sqlite3VdbeAddOp2(v, OP_MemStore, iLimit, 1);
    VdbeComment((v, "LIMIT counter"));
    sqlite3VdbeAddOp2(v, OP_IfMemZero, iLimit, iBreak);
    sqlite3VdbeAddOp2(v, OP_MemLoad, iLimit, 0);
  }
  if( p->pOffset ){
    p->iOffset = iOffset = ++pParse->nMem;
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) return;
    sqlite3ExprCode(pParse, p->pOffset);
    sqlite3VdbeAddOp2(v, OP_MustBeInt, 0, 0);
    sqlite3VdbeAddOp2(v, OP_MemStore, iOffset, p->pLimit==0);
    VdbeComment((v, "OFFSET counter"));
    addr1 = sqlite3VdbeAddOp2(v, OP_IfMemPos, iOffset, 0);
    sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
    sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
................................................................................
  pAggInfo->directMode = 1;
  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
    int nArg;
    int addrNext = 0;
    ExprList *pList = pF->pExpr->pList;
    if( pList ){
      nArg = pList->nExpr;
      sqlite3ExprCodeExprList(pParse, pList);
    }else{
      nArg = 0;
    }
    if( pF->iDistinct>=0 ){
      addrNext = sqlite3VdbeMakeLabel(v);
      assert( nArg==1 );
      codeDistinct_OLD(v, pF->iDistinct, addrNext, 1);
................................................................................
    sqlite3VdbeAddOp4(v, OP_AggStep, pF->iMem, nArg, 0, 
                      (void*)pF->pFunc, P4_FUNCDEF);
    if( addrNext ){
      sqlite3VdbeResolveLabel(v, addrNext);
    }
  }
  for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
    sqlite3ExprCode(pParse, pC->pExpr);
    sqlite3VdbeAddOp2(v, OP_MemStore, pC->iMem, 1);
  }
  pAggInfo->directMode = 0;
}

#ifndef SQLITE_OMIT_TRIGGER
/*
** This function is used when a SELECT statement is used to create a
................................................................................
      }else{
        /* Rows are coming out in undetermined order.  We have to push
        ** each row into a sorting index, terminate the first loop,
        ** then loop over the sorting index in order to get the output
        ** in sorted order
        */
        groupBySort = 1;
        sqlite3ExprCodeExprList(pParse, pGroupBy);
        sqlite3VdbeAddOp2(v, OP_Sequence, sAggInfo.sortingIdx, 0);
        j = pGroupBy->nExpr+1;
        for(i=0; i<sAggInfo.nColumn; i++){
          struct AggInfo_col *pCol = &sAggInfo.aCol[i];
          if( pCol->iSorterColumn<j ) continue;
          sqlite3ExprCodeGetColumn(v, pCol->pTab, pCol->iColumn,pCol->iTable,0);
          j++;
................................................................................
      */
      addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
      for(j=0; j<pGroupBy->nExpr; j++){
        if( groupBySort ){
          sqlite3VdbeAddOp2(v, OP_Column, sAggInfo.sortingIdx, j);
        }else{
          sAggInfo.directMode = 1;
          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr);
        }
        sqlite3VdbeAddOp2(v, OP_MemStore, iBMem+j, j<pGroupBy->nExpr-1);
      }
      for(j=pGroupBy->nExpr-1; j>=0; j--){
        if( j<pGroupBy->nExpr-1 ){
          sqlite3VdbeAddOp2(v, OP_MemLoad, iBMem+j, 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 SELECT statements in SQLite.
**
** $Id: select.c,v 1.383 2008/01/03 23:44:53 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.
................................................................................
*/
static void pushOntoSorter(
  Parse *pParse,         /* Parser context */
  ExprList *pOrderBy,    /* The ORDER BY clause */
  Select *pSelect        /* The whole SELECT statement */
){
  Vdbe *v = pParse->pVdbe;
  sqlite3ExprCodeExprList(pParse, pOrderBy, 0);
  sqlite3VdbeAddOp2(v, OP_Sequence, pOrderBy->iECursor, 0);
  sqlite3VdbeAddOp2(v, OP_Pull, pOrderBy->nExpr + 1, 0);
  sqlite3VdbeAddOp2(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0);
  sqlite3VdbeAddOp2(v, OP_IdxInsert, pOrderBy->iECursor, 0);
  if( pSelect->iLimit>=0 ){
    int addr1, addr2;
    addr1 = sqlite3VdbeAddOp2(v, OP_IfMemZero, pSelect->iLimit+1, 0);
................................................................................
      sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, iMem+i+1);
    }
  }else if( eDest!=SRT_Exists ){
    /* If the destination is an EXISTS(...) expression, the actual
    ** values returned by the SELECT are not required.
    */
    for(i=0; i<n; i++){
      sqlite3ExprCode(pParse, pEList->a[i].pExpr, iMem+i+1);
    }
  }
  nColumn = n;

  /* If the DISTINCT keyword was present on the SELECT statement
  ** and this row has been seen before, then do not make this row
  ** part of the result.
................................................................................
  ** no rows.
  */
  if( p->pLimit ){
    p->iLimit = iLimit = ++pParse->nMem;
    pParse->nMem++;
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) return;
    sqlite3ExprCode(pParse, p->pLimit, 0);
    sqlite3VdbeAddOp2(v, OP_MustBeInt, 0, 0);
    sqlite3VdbeAddOp2(v, OP_MemStore, iLimit, 1);
    VdbeComment((v, "LIMIT counter"));
    sqlite3VdbeAddOp2(v, OP_IfMemZero, iLimit, iBreak);
    sqlite3VdbeAddOp2(v, OP_MemLoad, iLimit, 0);
  }
  if( p->pOffset ){
    p->iOffset = iOffset = ++pParse->nMem;
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) return;
    sqlite3ExprCode(pParse, p->pOffset, 0);
    sqlite3VdbeAddOp2(v, OP_MustBeInt, 0, 0);
    sqlite3VdbeAddOp2(v, OP_MemStore, iOffset, p->pLimit==0);
    VdbeComment((v, "OFFSET counter"));
    addr1 = sqlite3VdbeAddOp2(v, OP_IfMemPos, iOffset, 0);
    sqlite3VdbeAddOp2(v, OP_Pop, 1, 0);
    sqlite3VdbeAddOp2(v, OP_Integer, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
................................................................................
  pAggInfo->directMode = 1;
  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
    int nArg;
    int addrNext = 0;
    ExprList *pList = pF->pExpr->pList;
    if( pList ){
      nArg = pList->nExpr;
      sqlite3ExprCodeExprList(pParse, pList, 0);
    }else{
      nArg = 0;
    }
    if( pF->iDistinct>=0 ){
      addrNext = sqlite3VdbeMakeLabel(v);
      assert( nArg==1 );
      codeDistinct_OLD(v, pF->iDistinct, addrNext, 1);
................................................................................
    sqlite3VdbeAddOp4(v, OP_AggStep, pF->iMem, nArg, 0, 
                      (void*)pF->pFunc, P4_FUNCDEF);
    if( addrNext ){
      sqlite3VdbeResolveLabel(v, addrNext);
    }
  }
  for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
    sqlite3ExprCode(pParse, pC->pExpr, pC->iMem);

  }
  pAggInfo->directMode = 0;
}

#ifndef SQLITE_OMIT_TRIGGER
/*
** This function is used when a SELECT statement is used to create a
................................................................................
      }else{
        /* Rows are coming out in undetermined order.  We have to push
        ** each row into a sorting index, terminate the first loop,
        ** then loop over the sorting index in order to get the output
        ** in sorted order
        */
        groupBySort = 1;
        sqlite3ExprCodeExprList(pParse, pGroupBy, 0);
        sqlite3VdbeAddOp2(v, OP_Sequence, sAggInfo.sortingIdx, 0);
        j = pGroupBy->nExpr+1;
        for(i=0; i<sAggInfo.nColumn; i++){
          struct AggInfo_col *pCol = &sAggInfo.aCol[i];
          if( pCol->iSorterColumn<j ) continue;
          sqlite3ExprCodeGetColumn(v, pCol->pTab, pCol->iColumn,pCol->iTable,0);
          j++;
................................................................................
      */
      addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
      for(j=0; j<pGroupBy->nExpr; j++){
        if( groupBySort ){
          sqlite3VdbeAddOp2(v, OP_Column, sAggInfo.sortingIdx, j);
        }else{
          sAggInfo.directMode = 1;
          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr, 0);
        }
        sqlite3VdbeAddOp2(v, OP_MemStore, iBMem+j, j<pGroupBy->nExpr-1);
      }
      for(j=pGroupBy->nExpr-1; j>=0; j--){
        if( j<pGroupBy->nExpr-1 ){
          sqlite3VdbeAddOp2(v, OP_MemLoad, iBMem+j, 0);
        }

**    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 1.635 2008/01/03 18:44:59 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** The macro unlikely() is a hint that surrounds a boolean
** expression that is usually false.  Macro likely() surrounds
................................................................................
int sqlite3IsReadOnly(Parse*, Table*, int);
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**);
void sqlite3WhereEnd(WhereInfo*);
void sqlite3ExprCodeGetColumn(Vdbe*, Table*, int, int, int);
void sqlite3ExprCode(Parse*, Expr*);
void sqlite3ExprCodeAndCache(Parse*, Expr*);
int sqlite3ExprIntoReg(Parse*,Expr*,int);
int sqlite3ExprCodeExprList(Parse*, ExprList*);
void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
Table *sqlite3FindTable(sqlite3*,const char*, const char*);
Table *sqlite3LocateTable(Parse*,const char*, const char*);
Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);
void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);

**    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 1.636 2008/01/03 23:44:53 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** The macro unlikely() is a hint that surrounds a boolean
** expression that is usually false.  Macro likely() surrounds
................................................................................
int sqlite3IsReadOnly(Parse*, Table*, int);
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**);
void sqlite3WhereEnd(WhereInfo*);
void sqlite3ExprCodeGetColumn(Vdbe*, Table*, int, int, int);
int sqlite3ExprCode(Parse*, Expr*, int);
void sqlite3ExprCodeAndCache(Parse*, Expr*);

int sqlite3ExprCodeExprList(Parse*, ExprList*, int);
void sqlite3ExprIfTrue(Parse*, Expr*, int, int);
void sqlite3ExprIfFalse(Parse*, Expr*, int, int);
Table *sqlite3FindTable(sqlite3*,const char*, const char*);
Table *sqlite3LocateTable(Parse*,const char*, const char*);
Index *sqlite3FindIndex(sqlite3*,const char*, const char*);
void sqlite3UnlinkAndDeleteTable(sqlite3*,int,const char*);
void sqlite3UnlinkAndDeleteIndex(sqlite3*,int,const char*);

**    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 1.154 2008/01/03 18:03:09 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Forward declaration */
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */
................................................................................
    sqlite3VdbeAddOp2(v, OP_MemLoad, mem1, 0);

    /* If the record number will change, push the record number as it
    ** will be after the update. (The old record number is currently
    ** on top of the stack.)
    */
    if( chngRowid ){
      sqlite3ExprCode(pParse, pRowidExpr);
      sqlite3VdbeAddOp2(v, OP_MustBeInt, 0, 0);
    }

    /* Compute new data for this record.  
    */
    for(i=0; i<pTab->nCol; i++){
      if( i==pTab->iPKey ){
................................................................................
        continue;
      }
      j = aXRef[i];
      if( j<0 ){
        sqlite3VdbeAddOp2(v, OP_Column, iCur, i);
        sqlite3ColumnDefault(v, pTab, i);
      }else{
        sqlite3ExprCode(pParse, pChanges->a[j].pExpr);
      }
    }

    /* Do constraint checks
    */
    sqlite3GenerateConstraintChecks(pParse, pTab, iCur, aIdxUsed, chngRowid, 1,
                                   onError, addr);

**    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 1.155 2008/01/03 23:44:53 drh Exp $
*/
#include "sqliteInt.h"

#ifndef SQLITE_OMIT_VIRTUALTABLE
/* Forward declaration */
static void updateVirtualTable(
  Parse *pParse,       /* The parsing context */
................................................................................
    sqlite3VdbeAddOp2(v, OP_MemLoad, mem1, 0);

    /* If the record number will change, push the record number as it
    ** will be after the update. (The old record number is currently
    ** on top of the stack.)
    */
    if( chngRowid ){
      sqlite3ExprCode(pParse, pRowidExpr, 0);
      sqlite3VdbeAddOp2(v, OP_MustBeInt, 0, 0);
    }

    /* Compute new data for this record.  
    */
    for(i=0; i<pTab->nCol; i++){
      if( i==pTab->iPKey ){
................................................................................
        continue;
      }
      j = aXRef[i];
      if( j<0 ){
        sqlite3VdbeAddOp2(v, OP_Column, iCur, i);
        sqlite3ColumnDefault(v, pTab, i);
      }else{
        sqlite3ExprCode(pParse, pChanges->a[j].pExpr, 0);
      }
    }

    /* Do constraint checks
    */
    sqlite3GenerateConstraintChecks(pParse, pTab, iCur, aIdxUsed, chngRowid, 1,
                                   onError, addr);

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.271 2008/01/03 18:39:42 danielk1977 Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
  Parse *pParse,      /* The parsing context */
  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
  WhereLevel *pLevel  /* When level of the FROM clause we are working on */
){
  Expr *pX = pTerm->pExpr;
  Vdbe *v = pParse->pVdbe;
  if( pX->op==TK_EQ ){
    sqlite3ExprCode(pParse, pX->pRight);
  }else if( pX->op==TK_ISNULL ){
    sqlite3VdbeAddOp2(v, OP_Null, 0, 0);
#ifndef SQLITE_OMIT_SUBQUERY
  }else{
    int eType;
    int iTab;
    struct InLoop *pIn;
................................................................................
                                                  pBestIdx->aConstraint;

      for(j=1; j<=nConstraint; j++){
        int k;
        for(k=0; k<nConstraint; k++){
          if( aUsage[k].argvIndex==j ){
            int iTerm = aConstraint[k].iTermOffset;
            sqlite3ExprCode(pParse, wc.a[iTerm].pExpr->pRight);
            break;
          }
        }
        if( k==nConstraint ) break;
      }
      iReg = ++pParse->nMem;
      pParse->nMem++;
................................................................................
        pEnd = pTerm;
      }
      if( pStart ){
        Expr *pX;
        pX = pStart->pExpr;
        assert( pX!=0 );
        assert( pStart->leftCursor==iCur );
        sqlite3ExprCode(pParse, pX->pRight);
        sqlite3VdbeAddOp2(v, OP_ForceInt, pX->op==TK_LE || pX->op==TK_GT, brk);
        sqlite3VdbeAddOp2(v, bRev ? OP_MoveLt : OP_MoveGe, iCur, brk);
        VdbeComment((v, "pk"));
        disableTerm(pLevel, pStart);
      }else{
        sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, brk);
      }
      if( pEnd ){
        Expr *pX;
        pX = pEnd->pExpr;
        assert( pX!=0 );
        assert( pEnd->leftCursor==iCur );
        sqlite3ExprCode(pParse, pX->pRight);
        pLevel->iMem = ++pParse->nMem;
        sqlite3VdbeAddOp2(v, OP_MemStore, pLevel->iMem, 1);
        if( pX->op==TK_LT || pX->op==TK_GT ){
          testOp = bRev ? OP_Le : OP_Ge;
        }else{
          testOp = bRev ? OP_Lt : OP_Gt;
        }
................................................................................
      if( topLimit ){
        Expr *pX;
        int k = pIdx->aiColumn[j];
        pTerm = findTerm(&wc, iCur, k, notReady, topOp, pIdx);
        assert( pTerm!=0 );
        pX = pTerm->pExpr;
        assert( (pTerm->flags & TERM_CODED)==0 );
        sqlite3ExprCode(pParse, pX->pRight);
        sqlite3VdbeAddOp2(v, OP_IsNull, -(nEq*2+1), nxt);
        topEq = pTerm->eOperator & (WO_LE|WO_GE);
        disableTerm(pLevel, pTerm);
        testOp = OP_IdxGE;
      }else{
        testOp = nEq>0 ? OP_IdxGE : OP_Noop;
        topEq = 1;
................................................................................
      if( btmLimit ){
        Expr *pX;
        int k = pIdx->aiColumn[j];
        pTerm = findTerm(&wc, iCur, k, notReady, btmOp, pIdx);
        assert( pTerm!=0 );
        pX = pTerm->pExpr;
        assert( (pTerm->flags & TERM_CODED)==0 );
        sqlite3ExprCode(pParse, pX->pRight);
        sqlite3VdbeAddOp2(v, OP_IsNull, -(nEq+1), nxt);
        btmEq = pTerm->eOperator & (WO_LE|WO_GE);
        disableTerm(pLevel, pTerm);
      }else{
        btmEq = 1;
      }
      if( nEq>0 || btmLimit ){

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.272 2008/01/03 23:44:53 drh Exp $
*/
#include "sqliteInt.h"

/*
** The number of bits in a Bitmask.  "BMS" means "BitMask Size".
*/
#define BMS  (sizeof(Bitmask)*8)
................................................................................
  Parse *pParse,      /* The parsing context */
  WhereTerm *pTerm,   /* The term of the WHERE clause to be coded */
  WhereLevel *pLevel  /* When level of the FROM clause we are working on */
){
  Expr *pX = pTerm->pExpr;
  Vdbe *v = pParse->pVdbe;
  if( pX->op==TK_EQ ){
    sqlite3ExprCode(pParse, pX->pRight, 0);
  }else if( pX->op==TK_ISNULL ){
    sqlite3VdbeAddOp2(v, OP_Null, 0, 0);
#ifndef SQLITE_OMIT_SUBQUERY
  }else{
    int eType;
    int iTab;
    struct InLoop *pIn;
................................................................................
                                                  pBestIdx->aConstraint;

      for(j=1; j<=nConstraint; j++){
        int k;
        for(k=0; k<nConstraint; k++){
          if( aUsage[k].argvIndex==j ){
            int iTerm = aConstraint[k].iTermOffset;
            sqlite3ExprCode(pParse, wc.a[iTerm].pExpr->pRight, 0);
            break;
          }
        }
        if( k==nConstraint ) break;
      }
      iReg = ++pParse->nMem;
      pParse->nMem++;
................................................................................
        pEnd = pTerm;
      }
      if( pStart ){
        Expr *pX;
        pX = pStart->pExpr;
        assert( pX!=0 );
        assert( pStart->leftCursor==iCur );
        sqlite3ExprCode(pParse, pX->pRight, 0);
        sqlite3VdbeAddOp2(v, OP_ForceInt, pX->op==TK_LE || pX->op==TK_GT, brk);
        sqlite3VdbeAddOp2(v, bRev ? OP_MoveLt : OP_MoveGe, iCur, brk);
        VdbeComment((v, "pk"));
        disableTerm(pLevel, pStart);
      }else{
        sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, brk);
      }
      if( pEnd ){
        Expr *pX;
        pX = pEnd->pExpr;
        assert( pX!=0 );
        assert( pEnd->leftCursor==iCur );
        sqlite3ExprCode(pParse, pX->pRight, 0);
        pLevel->iMem = ++pParse->nMem;
        sqlite3VdbeAddOp2(v, OP_MemStore, pLevel->iMem, 1);
        if( pX->op==TK_LT || pX->op==TK_GT ){
          testOp = bRev ? OP_Le : OP_Ge;
        }else{
          testOp = bRev ? OP_Lt : OP_Gt;
        }
................................................................................
      if( topLimit ){
        Expr *pX;
        int k = pIdx->aiColumn[j];
        pTerm = findTerm(&wc, iCur, k, notReady, topOp, pIdx);
        assert( pTerm!=0 );
        pX = pTerm->pExpr;
        assert( (pTerm->flags & TERM_CODED)==0 );
        sqlite3ExprCode(pParse, pX->pRight, 0);
        sqlite3VdbeAddOp2(v, OP_IsNull, -(nEq*2+1), nxt);
        topEq = pTerm->eOperator & (WO_LE|WO_GE);
        disableTerm(pLevel, pTerm);
        testOp = OP_IdxGE;
      }else{
        testOp = nEq>0 ? OP_IdxGE : OP_Noop;
        topEq = 1;
................................................................................
      if( btmLimit ){
        Expr *pX;
        int k = pIdx->aiColumn[j];
        pTerm = findTerm(&wc, iCur, k, notReady, btmOp, pIdx);
        assert( pTerm!=0 );
        pX = pTerm->pExpr;
        assert( (pTerm->flags & TERM_CODED)==0 );
        sqlite3ExprCode(pParse, pX->pRight, 0);
        sqlite3VdbeAddOp2(v, OP_IsNull, -(nEq+1), nxt);
        btmEq = pTerm->eOperator & (WO_LE|WO_GE);
        disableTerm(pLevel, pTerm);
      }else{
        btmEq = 1;
      }
      if( nEq>0 || btmLimit ){