codeOffset(v, p, addrContinue);
    sqlite4VdbeAddOp2(v, OP_SorterData, iTab, regSortOut);
    sqlite4VdbeAddOp3(v, OP_Column, ptab2, pOrderBy->nExpr+1, regRow);
    sqlite4VdbeChangeP5(v, OPFLAG_CLEARCACHE);
  }else{
    addr = 1 + sqlite4VdbeAddOp2(v, OP_Sort, iTab, addrBreak);
    codeOffset(v, p, addrContinue);
    sqlite4VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr+1, regRow);
  }
  switch( eDest ){
    case SRT_Table:
    case SRT_EphemTab: {
      testcase( eDest==SRT_Table );
      testcase( eDest==SRT_EphemTab );
      sqlite4VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);

    codeOffset(v, p, addrContinue);
    sqlite4VdbeAddOp2(v, OP_SorterData, iTab, regSortOut);
    sqlite4VdbeAddOp3(v, OP_Column, ptab2, pOrderBy->nExpr+1, regRow);
    sqlite4VdbeChangeP5(v, OPFLAG_CLEARCACHE);
  }else{
    addr = 1 + sqlite4VdbeAddOp2(v, OP_Sort, iTab, addrBreak);
    codeOffset(v, p, addrContinue);
    /* sqlite4VdbeAddOp3(v, OP_Column, iTab, pOrderBy->nExpr+1, regRow); */
  }
  switch( eDest ){
    case SRT_Table:
    case SRT_EphemTab: {
      testcase( eDest==SRT_Table );
      testcase( eDest==SRT_EphemTab );
      sqlite4VdbeAddOp2(v, OP_NewRowid, iParm, regRowid);

  KVSize nKey;
  KVSize nProbe;
  int rc;
  KVByteArray aProbe[16];

  assert( iEnd==(+1) || iEnd==(-1) );  
  nProbe = sqlite4PutVarint64(aProbe, pC->iRoot);
  aProbe[nProbe++] = 16 - iEnd*12;

  rc = sqlite4KVCursorSeek(pCur, aProbe, nProbe, iEnd);
  if( rc==SQLITE_OK ){
    return SQLITE_CORRUPT;
  }
  if( rc==SQLITE_INEXACT ){
    rc = sqlite4KVCursorKey(pCur, &aKey, &nKey);
    if( rc==SQLITE_OK && (nKey<nProbe-1 || memcmp(aKey, aProbe, nProbe-1)!=0) ){
      rc = SQLITE_NOTFOUND;
    }
  }

  return rc;
}

/*
** Move a VDBE cursor to the next element in its table.
** Return SQLITE_NOTFOUND if the seek falls of the end of the table.
*/

  KVSize nKey;
  KVSize nProbe;
  int rc;
  KVByteArray aProbe[16];

  assert( iEnd==(+1) || iEnd==(-1) );  
  nProbe = sqlite4PutVarint64(aProbe, pC->iRoot);
  aProbe[nProbe] = 0xFF;

  rc = sqlite4KVCursorSeek(pCur, aProbe, nProbe+(iEnd==-1), iEnd);
  if( rc==SQLITE_OK ){
    rc = SQLITE_CORRUPT_BKPT;

  }else if( rc==SQLITE_INEXACT ){
    rc = sqlite4KVCursorKey(pCur, &aKey, &nKey);
    if( rc==SQLITE_OK && (nKey<nProbe || memcmp(aKey, aProbe, nProbe)!=0) ){
      rc = SQLITE_NOTFOUND;
    }
  }

  return rc;
}

/*
** Move a VDBE cursor to the next element in its table.
** Return SQLITE_NOTFOUND if the seek falls of the end of the table.
*/

  WhereClause *pWC,     /* The WHERE clause to be searched */
  int iCur,             /* Cursor number of LHS */
  int iColumn,          /* Column number of LHS */
  Bitmask notReady,     /* RHS must not overlap with this mask */
  u32 op,               /* Mask of WO_xx values describing operator */
  Index *pIdx           /* Must be compatible with this index, if not NULL */
){


  WhereTerm *pTerm;
  int k;

  assert( iCur>=0 );
  op &= WO_ALL;
  for(; pWC; pWC=pWC->pOuter){
    for(pTerm=pWC->a, k=pWC->nTerm; k; k--, pTerm++){
      if( pTerm->leftCursor==iCur
         && (pTerm->prereqRight & notReady)==0
         && pTerm->u.leftColumn==iColumn
         && (pTerm->eOperator & op)!=0
      ){
        if( iColumn>=0 && pIdx && pTerm->eOperator!=WO_ISNULL ){


          Expr *pX = pTerm->pExpr;
          CollSeq *pColl;
          char idxaff;
          int j;
          Parse *pParse = pWC->pParse;
  
          idxaff = pIdx->pTable->aCol[iColumn].affinity;
          if( !sqlite4IndexAffinityOk(pX, idxaff) ) continue;
  

          /* Figure out the collation sequence required from an index for
          ** it to be useful for optimising expression pX. Store this
          ** value in variable pColl.
          */
          assert(pX->pLeft);
          pColl = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
          assert(pColl || pParse->nErr);
  
          for(j=0; pIdx->aiColumn[j]!=iColumn; j++){
            if( NEVER(j>=pIdx->nColumn) ) return 0;



          }
          if( pColl && sqlite4StrICmp(pColl->zName, pIdx->azColl[j]) ) continue;




        }
        return pTerm;
      }
    }
  }
  return 0;
}
................................................................................
      return 1;
    }
  }

  return 0;
}


























/*
** This routine decides if pIdx can be used to satisfy the ORDER BY
** clause.  If it can, it returns 1.  If pIdx cannot satisfy the
** ORDER BY clause, this routine returns 0.
**
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
** left-most table in the FROM clause of that same SELECT statement and
................................................................................
  Index *pIdx,            /* The index we are testing */
  int base,               /* Cursor number for the table to be sorted */
  ExprList *pOrderBy,     /* The ORDER BY clause */
  int nEqCol,             /* Number of index columns with == constraints */
  int wsFlags,            /* Index usages flags */
  int *pbRev              /* Set to 1 if ORDER BY is DESC */
){
  int i, j;                       /* Loop counters */
  int sortOrder = 0;              /* XOR of index and ORDER BY sort direction */
  int nTerm;                      /* Number of ORDER BY terms */
  struct ExprList_item *pTerm;    /* A term of the ORDER BY clause */
  sqlite4 *db = pParse->db;




  if( !pOrderBy ) return 0;
  if( wsFlags & WHERE_COLUMN_IN ) return 0;
  if( pIdx->bUnordered ) return 0;



  nTerm = pOrderBy->nExpr;


  assert( nTerm>0 );


  /* Argument pIdx must either point to a 'real' named index structure, 
  ** or an index structure allocated on the stack by bestKVIndex() to
  ** represent the rowid index that is part of every table.  */
  assert( pIdx->zName || (pIdx->nColumn==1 && pIdx->aiColumn[0]==-1) );




  /* Match terms of the ORDER BY clause against columns of
  ** the index.
  **
  ** Note that indices have pIdx->nColumn regular columns plus
  ** one additional column containing the rowid.  The rowid column
  ** of the index is also allowed to match against the ORDER BY
  ** clause.
  */
  for(i=j=0, pTerm=pOrderBy->a; j<nTerm && i<=pIdx->nColumn; i++){
    Expr *pExpr;       /* The expression of the ORDER BY pTerm */
    CollSeq *pColl;    /* The collating sequence of pExpr */
    int termSortOrder; /* Sort order for this term */
    int iColumn;       /* The i-th column of the index.  -1 for rowid */
    int iSortOrder;    /* 1 for DESC, 0 for ASC on the i-th index term */
    const char *zColl; /* Name of the collating sequence for i-th index term */





    pExpr = pTerm->pExpr;
    if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ){
      /* Can not use an index sort on anything that is not a column in the
      ** left-most table of the FROM clause */
      break;

    }













    pColl = sqlite4ExprCollSeq(pParse, pExpr);
    if( !pColl ){
      pColl = db->pDfltColl;
    }
    if( pIdx->zName && i<pIdx->nColumn ){
      iColumn = pIdx->aiColumn[i];
      iSortOrder = pIdx->aSortOrder[i];
      zColl = pIdx->azColl[i];
    }else{
      iColumn = -1;





      iSortOrder = 0;
      zColl = pColl->zName;



    }
    if( pExpr->iColumn!=iColumn || sqlite4StrICmp(pColl->zName, zColl) ){
      /* Term j of the ORDER BY clause does not match column i of the index */

      if( i<nEqCol ){
        /* If an index column that is constrained by == fails to match an
        ** ORDER BY term, that is OK.  Just ignore that column of the index
        */
        continue;
      }else if( i==pIdx->nColumn ){
        /* Index column i is the rowid.  All other terms match. */


        break;
      }else{
        /* If an index column fails to match and is not constrained by ==
        ** then the index cannot satisfy the ORDER BY constraint.
        */
        return 0;
      }
    }
    assert( pIdx->aSortOrder!=0 || iColumn==-1 );
    assert( pTerm->sortOrder==0 || pTerm->sortOrder==1 );
    assert( iSortOrder==0 || iSortOrder==1 );
    termSortOrder = iSortOrder ^ pTerm->sortOrder;
    if( i>nEqCol ){
      if( termSortOrder!=sortOrder ){
        /* Indices can only be used if all ORDER BY terms past the
        ** equality constraints are all either DESC or ASC. */
        return 0;
      }
    }else{
      sortOrder = termSortOrder;
    }
    j++;
    pTerm++;

    if( iColumn<0 && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){
      /* If the indexed column is the primary key and everything matches
      ** so far and none of the ORDER BY terms to the right reference other
      ** tables in the join, then we are assured that the index can be used 
      ** to sort because the primary key is unique and so none of the other
      ** columns will make any difference
      */
      j = nTerm;
    }

  }

  *pbRev = sortOrder!=0;

  if( j>=nTerm ){
    /* All terms of the ORDER BY clause are covered by this index so
    ** this index can be used for sorting. */
    return 1;
  }

  if( pIdx->onError!=OE_None && i==pIdx->nColumn

      && (wsFlags & WHERE_COLUMN_NULL)==0
      && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){




    /* All terms of this index match some prefix of the ORDER BY clause
    ** and the index is UNIQUE and no terms on the tail of the ORDER BY
    ** clause reference other tables in a join.  If this is all true then
    ** the order by clause is superfluous.  Not that if the matching
    ** condition is IS NULL then the result is not necessarily unique
    ** even on a UNIQUE index, so disallow those cases. */



    return 1;





  }











  return 0;
}

/*
** Prepare a crude estimate of the logarithm of the input value.
** The results need not be exact.  This is only used for estimating
** the total cost of performing operations with O(logN) or O(NlogN)
................................................................................
    *pnRow = nRowEst;
    WHERETRACE(("IN row estimate: est=%g\n", nRowEst));
  }
  return rc;
}
#endif /* defined(SQLITE_ENABLE_STAT3) */


/*
** Find the best query plan for accessing a particular table.  Write the
** best query plan and its cost into the WhereCost object supplied as the
** last parameter.
**
** The lowest cost plan wins.  The cost is an estimate of the amount of
** CPU and disk I/O needed to process the requested result.
................................................................................
  ExprList *pOrderBy,         /* The ORDER BY clause */
  ExprList *pDistinct,        /* The select-list if query is DISTINCT */
  WhereCost *pCost            /* Lowest cost query plan */
){
  int iCur = pSrc->iCursor;   /* The cursor of the table to be accessed */
  Index *pProbe;              /* An index we are evaluating */
  Index *pFirst;              /* First index to evaluate */

  int eqTermMask;             /* Current mask of valid equality operators */
  int idxEqTermMask;          /* Index mask of valid equality operators */

  /* Initialize the cost to a worst-case value */
  memset(pCost, 0, sizeof(*pCost));
  pCost->rCost = SQLITE_BIG_DBL;

................................................................................
    eqTermMask = WO_EQ|WO_IN;
    pFirst = pSrc->pTab->pIndex;
  }
#else
  eqTermMask = idxEqTermMask;
  pFirst = pSrc->pTab->pIndex;
#endif


  /* Loop over all indices looking for the best one to use */
  for(pProbe=pFirst; pProbe; pProbe=pProbe->pNext){
    const tRowcnt * const aiRowEst = pProbe->aiRowEst;
    double cost;                /* Cost of using pProbe */
    double nRow;                /* Estimated number of rows in result set */
    double log10N = (double)1;  /* base-10 logarithm of nRow (inexact) */
................................................................................
    int bSort = !!pOrderBy;       /* True if external sort required */
    int bDist = !!pDistinct;      /* True if index cannot help with DISTINCT */
    int bLookup = 0;              /* True if not the PK index */
    WhereTerm *pTerm;             /* A single term of the WHERE clause */
#ifdef SQLITE_ENABLE_STAT3
    WhereTerm *pFirstTerm = 0;    /* First term matching the index */
#endif








    /* Determine the values of nEq and nInMul */
    for(nEq=0; nEq<pProbe->nColumn; nEq++){
      int j = pProbe->aiColumn[nEq];


      pTerm = findTerm(pWC, iCur, j, notReady, eqTermMask, pProbe);
      if( pTerm==0 ) break;
      wsFlags |= WHERE_COLUMN_EQ;
      testcase( pTerm->pWC!=pWC );
      if( pTerm->eOperator & WO_IN ){
        Expr *pExpr = pTerm->pExpr;
        wsFlags |= WHERE_COLUMN_IN;
        if( ExprHasProperty(pExpr, EP_xIsSelect) ){
................................................................................
    ** at most a single row. In this case set the WHERE_UNIQUE flag to 
    ** indicate this to the caller.
    **
    ** Otherwise, if the search may find more than one row, test to see if
    ** there is a range constraint on indexed column (nEq+1) that can be 
    ** optimized using the index. 
    */
    if( nEq==pProbe->nColumn && pProbe->onError!=OE_None ){
      testcase( wsFlags & WHERE_COLUMN_IN );
      testcase( wsFlags & WHERE_COLUMN_NULL );
      if( (wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_NULL))==0 ){
        wsFlags |= WHERE_UNIQUE;
      }
    }else if( pProbe->bUnordered==0 ){
      int j = (nEq==pProbe->nColumn ? -1 : pProbe->aiColumn[nEq]);
      if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pProbe) ){
        WhereTerm *pTop = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pProbe);
        WhereTerm *pBtm = findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pProbe);
        whereRangeScanEst(pParse, pProbe, nEq, pBtm, pTop, &rangeDiv);
        if( pTop ){
          nBound = 1;
          wsFlags |= WHERE_TOP_LIMIT;
................................................................................
    sqlite4VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
  }
}
#else
# define explainOneScan(u,v,w,x,y,z)
#endif /* SQLITE_OMIT_EXPLAIN */


/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
static Bitmask codeOneLoopStart(
  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
  int iLevel,          /* Which level of pWInfo->a[] should be coded */
................................................................................
  u16 wctrlFlags,      /* One of the WHERE_* flags defined in sqliteInt.h */
  Bitmask notReady,    /* Which tables are currently available */
  Expr *pWhere         /* Complete WHERE clause */
){
  int j, k;            /* Loop counters */
  int iCur;            /* The VDBE cursor for the table */
  int addrNxt;         /* Where to jump to continue with the next IN case */
  int omitTable;       /* True if we use the index only */
  int bRev;            /* True if we need to scan in reverse order */
  WhereLevel *pLevel;  /* The where level to be coded */
  WhereClause *pWC;    /* Decomposition of the entire WHERE clause */
  WhereTerm *pTerm;               /* A WHERE clause term */
  Parse *pParse;                  /* Parsing context */
  Vdbe *v;                        /* The prepared stmt under constructions */
  struct SrcList_item *pTabItem;  /* FROM clause term being coded */
................................................................................
  pParse = pWInfo->pParse;
  v = pParse->pVdbe;
  pWC = pWInfo->pWC;
  pLevel = &pWInfo->a[iLevel];
  pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
  iCur = pTabItem->iCursor;
  bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;
  omitTable = (pLevel->plan.wsFlags & WHERE_IDX_ONLY)!=0 
           && (wctrlFlags & WHERE_FORCE_TABLE)==0;

  /* Create labels for the "break" and "continue" instructions
  ** for the current loop.  Jump to addrBrk to break out of a loop.
  ** Jump to cont to go immediately to the next iteration of the
  ** loop.
  **
  ** When there is an IN operator, we also have a "addrNxt" label that
................................................................................
    Index *pIdx;                 /* The index we will be using */
    int iIdxCur;                 /* The VDBE cursor for the index */
    int nExtraReg = 0;           /* Number of extra registers needed */
    int op;                      /* Instruction opcode */
    char *zStartAff;             /* Affinity for start of range constraint */
    char *zEndAff;               /* Affinity for end of range constraint */
    int regEndKey;               /* Register for end-key */



    pIdx = pLevel->plan.u.pIdx;

    iIdxCur = pLevel->iIdxCur;
    k = (nEq==pIdx->nColumn ? -1 : pIdx->aiColumn[nEq]);


    /* If this loop satisfies a sort order (pOrderBy) request that 
    ** was passed to this function to implement a "SELECT min(x) ..." 
    ** query, then the caller will only allow the loop to run for
    ** a single iteration. This means that the first row returned
    ** should not have a NULL value stored in 'x'. If column 'x' is
    ** the first one after the nEq equality constraints in the index,
................................................................................
      isMinQuery = 1;
      nExtraReg = 1;
    }

    /* Find any inequality constraint terms for the start and end 
    ** of the range.  */
    if( pLevel->plan.wsFlags & WHERE_TOP_LIMIT ){
      pRangeEnd = findTerm(pWC, iCur, k, notReady, (WO_LT|WO_LE), pIdx);
      nExtraReg = 1;
    }
    if( pLevel->plan.wsFlags & WHERE_BTM_LIMIT ){
      pRangeStart = findTerm(pWC, iCur, k, notReady, (WO_GT|WO_GE), pIdx);
      nExtraReg = 1;
    }

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase. Ensure that nExtraReg registers are allocated
    ** immediately following the array.
................................................................................
  {
    /* Case 5:  There is no usable index.  We must do a complete
    **          scan of the entire table.
    */
    static const u8 aStep[] = { OP_Next, OP_Prev };
    static const u8 aStart[] = { OP_Rewind, OP_Last };
    assert( bRev==0 || bRev==1 );
    assert( omitTable==0 );
    pLevel->op = aStep[bRev];
    pLevel->p1 = iCur;
    pLevel->p2 = 1 + sqlite4VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
    pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
  }
  notReady &= ~getMask(pWC->pMaskSet, iCur);

  WhereClause *pWC,     /* The WHERE clause to be searched */
  int iCur,             /* Cursor number of LHS */
  int iColumn,          /* Column number of LHS */
  Bitmask notReady,     /* RHS must not overlap with this mask */
  u32 op,               /* Mask of WO_xx values describing operator */
  Index *pIdx           /* Must be compatible with this index, if not NULL */
){
  sqlite4 *db = pWC->pParse->db;  /* Database handle */
  Table *pTab = pIdx->pTable;     /* Table object for cursor iCur */
  WhereTerm *pTerm;
  int k;

  assert( iCur>=0 );
  op &= WO_ALL;
  for(; pWC; pWC=pWC->pOuter){
    for(pTerm=pWC->a, k=pWC->nTerm; k; k--, pTerm++){
      if( pTerm->leftCursor==iCur
         && (pTerm->prereqRight & notReady)==0
         && pTerm->u.leftColumn==iColumn
         && (pTerm->eOperator & op)!=0
      ){
        if( iColumn>=0 && pIdx && pTerm->eOperator!=WO_ISNULL ){
          const char *zColl;      /* Collation sequence used by index */
          CollSeq *pColl;         /* Collation sequence used by expression */
          Expr *pX = pTerm->pExpr;


          int j;
          Parse *pParse = pWC->pParse;
  
          if( !sqlite4IndexAffinityOk(pX, pTab->aCol[iColumn].affinity) ){
            continue;
          }
  
          /* Figure out the collation sequence used by expression pX. Store

          ** this in pColl. Also the collation sequence used by the index.
          ** Store this one in zColl.  */
          assert(pX->pLeft);
          pColl = sqlite4BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
          assert( pParse->nErr || (pColl && pColl->enc==pIdx->pSchema->enc)  );

          for(j=0; pIdx->aiColumn[j]!=iColumn && j<pIdx->nColumn; j++);
          if( j>=pIdx->nColumn ){
            zColl = pTab->aCol[iColumn].zColl;
          }else{
            zColl = pIdx->azColl[j];
          }


          /* If the collation sequence used by the index is not the same as
          ** that used by the expression, then this term is not a match.  */
          if( pColl!=sqlite4FindCollSeq(db, ENC(db), zColl, 0) ) continue;
        }
        return pTerm;
      }
    }
  }
  return 0;
}
................................................................................
      return 1;
    }
  }

  return 0;
}


/*
** Return the table column number of the iIdxCol'th field in the index
** keys used by index pIdx, including any appended PRIMARY KEY fields.
** If there is no iIdxCol'th field in index pIdx, return -2.
**
** Example:
**
**   CREATE TABLE t1(a, b, c, PRIMARY KEY(a, b));
**   CREATE INDEX i1 ON t1(c);
**
** Index i1 in the example above consists of three fields - the indexed
** field "c" followed by the two primary key fields. The automatic PRIMARY
** KEY index consists of two fields only.
*/
static int idxColumnNumber(Index *pIdx, Index *pPk, int iIdxCol){
  int iRet = -2;
  if( iIdxCol<pIdx->nColumn ){
    iRet = pIdx->aiColumn[iIdxCol];
  }else if( iIdxCol<(pIdx->nColumn + pPk->nColumn) ){
    iRet = pPk->aiColumn[iIdxCol - pIdx->nColumn];
  }
  return iRet;
}

/*
** This routine decides if pIdx can be used to satisfy the ORDER BY
** clause.  If it can, it returns 1.  If pIdx cannot satisfy the
** ORDER BY clause, this routine returns 0.
**
** pOrderBy is an ORDER BY clause from a SELECT statement.  pTab is the
** left-most table in the FROM clause of that same SELECT statement and
................................................................................
  Index *pIdx,            /* The index we are testing */
  int base,               /* Cursor number for the table to be sorted */
  ExprList *pOrderBy,     /* The ORDER BY clause */
  int nEqCol,             /* Number of index columns with == constraints */
  int wsFlags,            /* Index usages flags */
  int *pbRev              /* Set to 1 if ORDER BY is DESC */
){
  sqlite4 *db = pParse->db;       /* Database handle */
  int sortOrder = 0;              /* XOR of index and ORDER BY sort direction */
  int nTerm;                      /* Number of ORDER BY terms */
  int iTerm;                      /* Used to iterate through nTerm terms */
  int iNext = nEqCol;             /* Index of next unmatched column in index */
  int nIdxCol;                    /* Number of columns in index, incl. PK */
  Index *pPk;
  Table *pTab;

  if( !pOrderBy ) return 0;
  if( wsFlags & WHERE_COLUMN_IN ) return 0;
  if( pIdx->bUnordered ) return 0;

  pTab = pIdx->pTable;
  pPk = sqlite4FindPrimaryKey(pTab, 0);
  nTerm = pOrderBy->nExpr;
  nIdxCol = pIdx->nColumn + (pIdx==pPk ? 0 : pPk->nColumn);

  assert( nTerm>0 );
  assert( pIdx && pIdx->zName );





  for(iTerm=0; iTerm<nTerm; iTerm++){
    struct ExprList_item *pTerm;  /* iTerm'th term of ORDER BY clause */
    int iIdxCol;                  /* Index of column in index records */










    Expr *pExpr;       /* The expression of the ORDER BY pTerm */
    CollSeq *pColl;    /* The collating sequence of pExpr */
    int termSortOrder; /* Sort order for this term */
    int iColumn;       /* The i-th column of the index.  -1 for rowid */

    const char *zColl; /* Name of the collating sequence for i-th index term */

    /* Can not use an index sort on anything that is not a column in the
    ** left-most table of the FROM clause. Break out of the loop if this
    ** expression is anything other than that. */
    pTerm = &pOrderBy->a[iTerm];
    pExpr = pTerm->pExpr;
    if( pExpr->op!=TK_COLUMN || pExpr->iTable!=base ) break;



    iColumn = pExpr->iColumn;

    /* Check that column iColumn is a part of the index. If it is not, then
    ** this index may not be used as a sorting index. This block also checks
    ** that column iColumn is either the iNext'th column of the index, or
    ** else one of the nEqCol columns that the index guarantees will be 
    ** constant.  */
    for(iIdxCol=0; iIdxCol<nIdxCol; iIdxCol++){
      if( idxColumnNumber(pIdx, pPk, iIdxCol)==iColumn ) break;
    }
    if( iIdxCol==nIdxCol || (iIdxCol>=nEqCol && iIdxCol!=iNext) ) break;

    /* Check that the collation sequence used by the expression is the same
    ** as the collation sequence used by the index. If not, this is not a
    ** sorting index.  */
    pColl = sqlite4ExprCollSeq(pParse, pExpr);

    if( !pColl ) pColl = db->pDfltColl;

    if( iIdxCol<pIdx->nColumn ){


      zColl = pIdx->azColl[iIdxCol];
    }else{

      zColl = pTab->aCol[iColumn].zColl;
    }
    if( pColl!=sqlite4FindCollSeq(db, ENC(db), zColl, 0) ) break;

    if( iIdxCol==iNext ){
      u8 reqSortOrder;

      u8 idxSortOrder = SQLITE_SO_ASC;
      if( iIdxCol<pIdx->nColumn ) idxSortOrder = pIdx->aSortOrder[iIdxCol];
      assert( idxSortOrder==SQLITE_SO_ASC || idxSortOrder==SQLITE_SO_DESC );



      reqSortOrder = (idxSortOrder ^ pTerm->sortOrder);
      if( iNext==nEqCol ){






        sortOrder = reqSortOrder;
      }else if( sortOrder!=reqSortOrder ){
        break;





      }






      iNext++;



    }





#if 0
    if( iColumn<0 && !referencesOtherTables(pOrderBy, pMaskSet, j, base) ){
      /* If the indexed column is the primary key and everything matches
      ** so far and none of the ORDER BY terms to the right reference other
      ** tables in the join, then we are assured that the index can be used 
      ** to sort because the primary key is unique and so none of the other
      ** columns will make any difference
      */
      j = nTerm;
    }
#endif
  }

  *pbRev = sortOrder!=0;

  if( iTerm>=nTerm ){
    /* All terms of the ORDER BY clause are covered by this index. The
    ** index can therefore be used for sorting.  */
    return 1;
  }

  if( pIdx->onError!=OE_None
   && iNext>=pIdx->nColumn 
   && (wsFlags & WHERE_COLUMN_NULL)==0
   && !referencesOtherTables(pOrderBy, pMaskSet, iTerm, base) 
  ){

    if( iNext==nIdxCol ){
      /* All columns indexed by this UNIQUE index, and all PK columns are
      ** are matched by a prefix of the ORDER BY clause. And since the PK





      ** columns are guaranteed to be unique and NOT NULL, there is no way
      ** for the trailing ORDER BY terms to affect the sort order. Therefore,
      ** we have a sorting index.  */
      return 1;
    }else{
      int i;
      for(i=nEqCol; i<pIdx->nColumn; i++){
        int iCol = pIdx->aiColumn[i];
        if( iCol>=0 && pTab->aCol[iCol].notNull==0 ) break;
      }

      /* All columns indexed by this UNIQUE index are matched by a prefix
      ** of the ORDER BY clause. And there is reason to believe that none
      ** of the expressions in the ORDER BY prefix will evalulate to NULL.
      ** The index may be used for sorting in this case too since it is
      ** guaranteed that none of the trailing, unmatched ORDER BY terms 
      ** affect the sort order.  */
      return (i>=pIdx->nColumn);
    }
  }

  return 0;
}

/*
** Prepare a crude estimate of the logarithm of the input value.
** The results need not be exact.  This is only used for estimating
** the total cost of performing operations with O(logN) or O(NlogN)
................................................................................
    *pnRow = nRowEst;
    WHERETRACE(("IN row estimate: est=%g\n", nRowEst));
  }
  return rc;
}
#endif /* defined(SQLITE_ENABLE_STAT3) */


/*
** Find the best query plan for accessing a particular table.  Write the
** best query plan and its cost into the WhereCost object supplied as the
** last parameter.
**
** The lowest cost plan wins.  The cost is an estimate of the amount of
** CPU and disk I/O needed to process the requested result.
................................................................................
  ExprList *pOrderBy,         /* The ORDER BY clause */
  ExprList *pDistinct,        /* The select-list if query is DISTINCT */
  WhereCost *pCost            /* Lowest cost query plan */
){
  int iCur = pSrc->iCursor;   /* The cursor of the table to be accessed */
  Index *pProbe;              /* An index we are evaluating */
  Index *pFirst;              /* First index to evaluate */
  Index *pPk;                 /* Primary Key index */
  int eqTermMask;             /* Current mask of valid equality operators */
  int idxEqTermMask;          /* Index mask of valid equality operators */

  /* Initialize the cost to a worst-case value */
  memset(pCost, 0, sizeof(*pCost));
  pCost->rCost = SQLITE_BIG_DBL;

................................................................................
    eqTermMask = WO_EQ|WO_IN;
    pFirst = pSrc->pTab->pIndex;
  }
#else
  eqTermMask = idxEqTermMask;
  pFirst = pSrc->pTab->pIndex;
#endif
  pPk = sqlite4FindPrimaryKey(pSrc->pTab, 0);

  /* Loop over all indices looking for the best one to use */
  for(pProbe=pFirst; pProbe; pProbe=pProbe->pNext){
    const tRowcnt * const aiRowEst = pProbe->aiRowEst;
    double cost;                /* Cost of using pProbe */
    double nRow;                /* Estimated number of rows in result set */
    double log10N = (double)1;  /* base-10 logarithm of nRow (inexact) */
................................................................................
    int bSort = !!pOrderBy;       /* True if external sort required */
    int bDist = !!pDistinct;      /* True if index cannot help with DISTINCT */
    int bLookup = 0;              /* True if not the PK index */
    WhereTerm *pTerm;             /* A single term of the WHERE clause */
#ifdef SQLITE_ENABLE_STAT3
    WhereTerm *pFirstTerm = 0;    /* First term matching the index */
#endif
    int nCol = pProbe->nColumn;   /* Total columns in index record */

    /* Unless pProbe is the primary key index, then the encoded PK column 
    ** values are at the end of each record. Set variable nCol to the total
    ** number of columns encoded into each index record, including the PK  
    ** columns.  */
    if( pProbe!=pPk ) nCol += pPk->nColumn;

    /* Determine the values of nEq and nInMul */
    for(nEq=0; nEq<nCol; nEq++){

      int iCol;                   /* Table column of nEq'th index field */
      iCol = idxColumnNumber(pProbe, pPk, nEq);
      pTerm = findTerm(pWC, iCur, iCol, notReady, eqTermMask, pProbe);
      if( pTerm==0 ) break;
      wsFlags |= WHERE_COLUMN_EQ;
      testcase( pTerm->pWC!=pWC );
      if( pTerm->eOperator & WO_IN ){
        Expr *pExpr = pTerm->pExpr;
        wsFlags |= WHERE_COLUMN_IN;
        if( ExprHasProperty(pExpr, EP_xIsSelect) ){
................................................................................
    ** at most a single row. In this case set the WHERE_UNIQUE flag to 
    ** indicate this to the caller.
    **
    ** Otherwise, if the search may find more than one row, test to see if
    ** there is a range constraint on indexed column (nEq+1) that can be 
    ** optimized using the index. 
    */
    if( nEq>=pProbe->nColumn && pProbe->onError!=OE_None ){
      testcase( wsFlags & WHERE_COLUMN_IN );
      testcase( wsFlags & WHERE_COLUMN_NULL );
      if( (wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_NULL))==0 ){
        wsFlags |= WHERE_UNIQUE;
      }
    }else if( pProbe->bUnordered==0 ){
      int j = idxColumnNumber(pProbe, pPk, nEq);
      if( findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE|WO_GT|WO_GE, pProbe) ){
        WhereTerm *pTop = findTerm(pWC, iCur, j, notReady, WO_LT|WO_LE, pProbe);
        WhereTerm *pBtm = findTerm(pWC, iCur, j, notReady, WO_GT|WO_GE, pProbe);
        whereRangeScanEst(pParse, pProbe, nEq, pBtm, pTop, &rangeDiv);
        if( pTop ){
          nBound = 1;
          wsFlags |= WHERE_TOP_LIMIT;
................................................................................
    sqlite4VdbeAddOp4(v, OP_Explain, iId, iLevel, iFrom, zMsg, P4_DYNAMIC);
  }
}
#else
# define explainOneScan(u,v,w,x,y,z)
#endif /* SQLITE_OMIT_EXPLAIN */


/*
** Generate code for the start of the iLevel-th loop in the WHERE clause
** implementation described by pWInfo.
*/
static Bitmask codeOneLoopStart(
  WhereInfo *pWInfo,   /* Complete information about the WHERE clause */
  int iLevel,          /* Which level of pWInfo->a[] should be coded */
................................................................................
  u16 wctrlFlags,      /* One of the WHERE_* flags defined in sqliteInt.h */
  Bitmask notReady,    /* Which tables are currently available */
  Expr *pWhere         /* Complete WHERE clause */
){
  int j, k;            /* Loop counters */
  int iCur;            /* The VDBE cursor for the table */
  int addrNxt;         /* Where to jump to continue with the next IN case */

  int bRev;            /* True if we need to scan in reverse order */
  WhereLevel *pLevel;  /* The where level to be coded */
  WhereClause *pWC;    /* Decomposition of the entire WHERE clause */
  WhereTerm *pTerm;               /* A WHERE clause term */
  Parse *pParse;                  /* Parsing context */
  Vdbe *v;                        /* The prepared stmt under constructions */
  struct SrcList_item *pTabItem;  /* FROM clause term being coded */
................................................................................
  pParse = pWInfo->pParse;
  v = pParse->pVdbe;
  pWC = pWInfo->pWC;
  pLevel = &pWInfo->a[iLevel];
  pTabItem = &pWInfo->pTabList->a[pLevel->iFrom];
  iCur = pTabItem->iCursor;
  bRev = (pLevel->plan.wsFlags & WHERE_REVERSE)!=0;



  /* Create labels for the "break" and "continue" instructions
  ** for the current loop.  Jump to addrBrk to break out of a loop.
  ** Jump to cont to go immediately to the next iteration of the
  ** loop.
  **
  ** When there is an IN operator, we also have a "addrNxt" label that
................................................................................
    Index *pIdx;                 /* The index we will be using */
    int iIdxCur;                 /* The VDBE cursor for the index */
    int nExtraReg = 0;           /* Number of extra registers needed */
    int op;                      /* Instruction opcode */
    char *zStartAff;             /* Affinity for start of range constraint */
    char *zEndAff;               /* Affinity for end of range constraint */
    int regEndKey;               /* Register for end-key */
    int iIneq;                   /* The table column subject to inequality */
    Index *pPk;                  /* Primary key index on same table as pIdx */

    pIdx = pLevel->plan.u.pIdx;
    pPk = sqlite4FindPrimaryKey(pIdx->pTable, 0);
    iIdxCur = pLevel->iIdxCur;

    iIneq = idxColumnNumber(pIdx, pPk, nEq);

    /* If this loop satisfies a sort order (pOrderBy) request that 
    ** was passed to this function to implement a "SELECT min(x) ..." 
    ** query, then the caller will only allow the loop to run for
    ** a single iteration. This means that the first row returned
    ** should not have a NULL value stored in 'x'. If column 'x' is
    ** the first one after the nEq equality constraints in the index,
................................................................................
      isMinQuery = 1;
      nExtraReg = 1;
    }

    /* Find any inequality constraint terms for the start and end 
    ** of the range.  */
    if( pLevel->plan.wsFlags & WHERE_TOP_LIMIT ){
      pRangeEnd = findTerm(pWC, iCur, iIneq, notReady, (WO_LT|WO_LE), pIdx);
      nExtraReg = 1;
    }
    if( pLevel->plan.wsFlags & WHERE_BTM_LIMIT ){
      pRangeStart = findTerm(pWC, iCur, iIneq, notReady, (WO_GT|WO_GE), pIdx);
      nExtraReg = 1;
    }

    /* Generate code to evaluate all constraint terms using == or IN
    ** and store the values of those terms in an array of registers
    ** starting at regBase. Ensure that nExtraReg registers are allocated
    ** immediately following the array.
................................................................................
  {
    /* Case 5:  There is no usable index.  We must do a complete
    **          scan of the entire table.
    */
    static const u8 aStep[] = { OP_Next, OP_Prev };
    static const u8 aStart[] = { OP_Rewind, OP_Last };
    assert( bRev==0 || bRev==1 );

    pLevel->op = aStep[bRev];
    pLevel->p1 = iCur;
    pLevel->p2 = 1 + sqlite4VdbeAddOp2(v, aStart[bRev], iCur, addrBrk);
    pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
  }
  notReady &= ~getMask(pWC->pMaskSet, iCur);

#   veryquick
#   quick
#   full
#
lappend ::testsuitelist xxx

test_suite "src4" -prefix "" -description {
} -files [
  test_set simple.test fkey1.test conflict.test trigger2.test select1.test
]



test_suite "veryquick" -prefix "" -description {
  "Very" quick test suite. Runs in less than 5 minutes on a workstation. 
  This test suite is the same as the "quick" tests, except that some files
  that test malloc and IO errors are omitted.
} -files [
  test_set $allquicktests -exclude *malloc* *ioerr* *fault*

#   veryquick
#   quick
#   full
#
lappend ::testsuitelist xxx

test_suite "src4" -prefix "" -description {
} -files {
  simple.test fkey1.test conflict.test trigger2.test select1.test

  where.test
}

test_suite "veryquick" -prefix "" -description {
  "Very" quick test suite. Runs in less than 5 minutes on a workstation. 
  This test suite is the same as the "quick" tests, except that some files
  that test malloc and IO errors are omitted.
} -files [
  test_set $allquicktests -exclude *malloc* *ioerr* *fault*

#
# do_test where-1.26 {
#   count {SELECT w FROM t1 WHERE x=3 AND y BETWEEN 121 AND 196}
# } {10 11 12 13 9}

do_test where-1.27 {
  count {SELECT w FROM t1 WHERE x=3 AND y+1==122}
} {10 10}

do_test where-1.28 {
  count {SELECT w FROM t1 WHERE x+1=4 AND y+1==122}
} {10 99}
do_test where-1.29 {
  count {SELECT w FROM t1 WHERE y==121}
} {10 99}


do_test where-1.30 {
  count {SELECT w FROM t1 WHERE w>97}
} {98 99 100 3}
do_test where-1.31 {
  count {SELECT w FROM t1 WHERE w>=97}
} {97 98 99 100 4}
do_test where-1.33 {
  count {SELECT w FROM t1 WHERE w==97}
} {97 2}
do_test where-1.33.1  {
  count {SELECT w FROM t1 WHERE w<=97 AND w==97}
} {97 2}
do_test where-1.33.2  {
  count {SELECT w FROM t1 WHERE w<98 AND w==97}
} {97 2}
do_test where-1.33.3  {
  count {SELECT w FROM t1 WHERE w>=97 AND w==97}
} {97 2}
do_test where-1.33.4  {
  count {SELECT w FROM t1 WHERE w>96 AND w==97}
} {97 2}
do_test where-1.33.5  {
  count {SELECT w FROM t1 WHERE w==97 AND w==97}
} {97 2}
do_test where-1.34 {
  count {SELECT w FROM t1 WHERE w+1==98}
} {97 99}
do_test where-1.35 {
  count {SELECT w FROM t1 WHERE w<3}
} {1 2 2}
do_test where-1.36 {
  count {SELECT w FROM t1 WHERE w<=3}
} {1 2 3 3}
do_test where-1.37 {
  count {SELECT w FROM t1 WHERE w+1<=4 ORDER BY w}
} {1 2 3 99}

do_test where-1.38 {
  count {SELECT (w) FROM t1 WHERE (w)>(97)}
} {98 99 100 3}
do_test where-1.39 {
  count {SELECT (w) FROM t1 WHERE (w)>=(97)}
} {97 98 99 100 4}
do_test where-1.40 {
  count {SELECT (w) FROM t1 WHERE (w)==(97)}
} {97 2}
do_test where-1.41 {
  count {SELECT (w) FROM t1 WHERE ((w)+(1))==(98)}
} {97 99}


# Do the same kind of thing except use a join as the data source.
#
do_test where-2.1 {
  count {
    SELECT w, p FROM t2, t1
................................................................................
# Lets do a 3-way join.
#
do_test where-3.1 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE C.w=101-B.p AND B.r=10202-A.y AND A.w=11
  }
} {11 90 11 8}
do_test where-3.2 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE C.w=101-B.p AND B.r=10202-A.y AND A.w=12
  }
} {12 89 12 8}
do_test where-3.3 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE A.w=15 AND B.p=C.w AND B.r=10202-A.y
  }
} {15 86 86 8}

# Test to see that the special case of a constant WHERE clause is
# handled.
#
do_test where-4.1 {
  count {
    SELECT * FROM t1 WHERE 0
  }
} {0}
do_test where-4.2 {
  count {
    SELECT * FROM t1 WHERE 1 LIMIT 1
  }
} {1 0 4 0}
do_test where-4.3 {
  execsql {
    SELECT 99 WHERE 0
  }
} {}
do_test where-4.4 {
  execsql {
................................................................................
# Omit these tests if the build is not capable of sub-queries.
#
ifcapable subquery {
  do_test where-5.1 {
    count {
      SELECT * FROM t1 WHERE rowid IN (1,2,3,1234) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 4}
  do_test where-5.2 {
    count {
      SELECT * FROM t1 WHERE rowid+0 IN (1,2,3,1234) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 102}
  do_test where-5.3 {
    count {
      SELECT * FROM t1 WHERE w IN (-1,1,2,3) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 14}
  do_test where-5.4 {
    count {
      SELECT * FROM t1 WHERE w+0 IN (-1,1,2,3) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 102}
  do_test where-5.5 {
    count {
      SELECT * FROM t1 WHERE rowid IN 
         (select rowid from t1 where rowid IN (-1,2,4))
      ORDER BY 1;
    }
  } {2 1 9 4 2 25 3}
  do_test where-5.6 {
    count {
      SELECT * FROM t1 WHERE rowid+0 IN 
         (select rowid from t1 where rowid IN (-1,2,4))
      ORDER BY 1;
    }
  } {2 1 9 4 2 25 103}
  do_test where-5.7 {
    count {
      SELECT * FROM t1 WHERE w IN 
         (select rowid from t1 where rowid IN (-1,2,4))
      ORDER BY 1;
    }
  } {2 1 9 4 2 25 9}
  do_test where-5.8 {
    count {
      SELECT * FROM t1 WHERE w+0 IN 
         (select rowid from t1 where rowid IN (-1,2,4))
      ORDER BY 1;
    }
  } {2 1 9 4 2 25 103}
  do_test where-5.9 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) ORDER BY 1;
    }
  } {2 1 9 3 1 16 7}
  do_test where-5.10 {
    count {
      SELECT * FROM t1 WHERE x+0 IN (1,7) ORDER BY 1;
    }
  } {2 1 9 3 1 16 199}
  do_test where-5.11 {
    count {
      SELECT * FROM t1 WHERE y IN (6400,8100) ORDER BY 1;
    }
  } {79 6 6400 89 6 8100 199}
  do_test where-5.12 {
    count {
      SELECT * FROM t1 WHERE x=6 AND y IN (6400,8100) ORDER BY 1;
    }
  } {79 6 6400 89 6 8100 7}
  do_test where-5.13 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) AND y NOT IN (6400,8100) ORDER BY 1;
    }
  } {2 1 9 3 1 16 7}
  do_test where-5.14 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) AND y IN (9,10) ORDER BY 1;
    }
  } {2 1 9 8}
  do_test where-5.15 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) AND y IN (9,16) ORDER BY 1;
    }
  } {2 1 9 3 1 16 11}
}

# This procedure executes the SQL.  Then it checks to see if the OP_Sort
# opcode was executed.  If an OP_Sort did occur, then "sort" is appended
# to the result.  If no OP_Sort happened, then "nosort" is appended.
#
# This procedure is used to check to make sure sorting is or is not
................................................................................
  }
} {1 100 4 2 99 9 3 98 16 sort}
do_test where-6.4 {
  cksort {
    SELECT * FROM t3 WHERE a<10 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

do_test where-6.5 {
  cksort {
    SELECT * FROM t3 WHERE a>0 AND a<10 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}
do_test where-6.6 {
  cksort {
    SELECT * FROM t3 WHERE a>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

do_test where-6.7 {


  cksort {
    SELECT * FROM t3 WHERE b>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

ifcapable subquery {
  do_test where-6.8 {
    cksort {
      SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a LIMIT 3
    }
  } {1 100 4 2 99 9 3 98 16 sort}
}
................................................................................
} {1 100 4 nosort}
do_test where-6.9.6 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY c DESC LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.7 {

  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY c,a LIMIT 3
  }
} {1 100 4 sort}
do_test where-6.9.8 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a DESC, c ASC LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.9 {
  cksort {
................................................................................
  }
} {4 9 16 nosort}
do_test where-6.20 {
  cksort {
    SELECT y FROM t1 ORDER BY rowid LIMIT 3;
  }
} {4 9 16 nosort}

do_test where-6.21 {
  cksort {
    SELECT y FROM t1 ORDER BY rowid, y LIMIT 3;
  }
} {4 9 16 nosort}

do_test where-6.22 {
  cksort {
    SELECT y FROM t1 ORDER BY rowid, y DESC LIMIT 3;
  }
} {4 9 16 nosort}
do_test where-6.23 {
  cksort {
................................................................................
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, x.b DESC
  } 
} {1/1 1/4 4/1 4/4 nosort}
do_test where-14.5 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, x.a||x.b
  } 
} {4/1 4/4 1/1 1/4 nosort}
do_test where-14.6 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, x.a||x.b DESC
  } 
} {4/1 4/4 1/1 1/4 nosort}
do_test where-14.7 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, y.a||y.b
  } 
} {4/1 4/4 1/1 1/4 sort}
do_test where-14.7.1 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, x.a, y.a||y.b
  } 
} {4/1 4/4 1/1 1/4 sort}

do_test where-14.7.2 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, x.a, x.a||x.b
  } 
} {4/1 4/4 1/1 1/4 nosort}

do_test where-14.8 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, y.a||y.b DESC
  } 
} {4/4 4/1 1/4 1/1 sort}
do_test where-14.9 {
  cksort {

#
# do_test where-1.26 {
#   count {SELECT w FROM t1 WHERE x=3 AND y BETWEEN 121 AND 196}
# } {10 11 12 13 9}

do_test where-1.27 {
  count {SELECT w FROM t1 WHERE x=3 AND y+1==122}
} {10 17}

do_test where-1.28 {
  count {SELECT w FROM t1 WHERE x+1=4 AND y+1==122}
} {10 101}
do_test where-1.29 {
  count {SELECT w FROM t1 WHERE y==121}
} {10 101}


do_test where-1.30 {
  count {SELECT w FROM t1 WHERE w>97}
} {98 99 100 7}
do_test where-1.31 {
  count {SELECT w FROM t1 WHERE w>=97}
} {97 98 99 100 9}
do_test where-1.33 {
  count {SELECT w FROM t1 WHERE w==97}
} {97 3}
do_test where-1.33.1  {
  count {SELECT w FROM t1 WHERE w<=97 AND w==97}
} {97 3}
do_test where-1.33.2  {
  count {SELECT w FROM t1 WHERE w<98 AND w==97}
} {97 3}
do_test where-1.33.3  {
  count {SELECT w FROM t1 WHERE w>=97 AND w==97}
} {97 3}
do_test where-1.33.4  {
  count {SELECT w FROM t1 WHERE w>96 AND w==97}
} {97 3}
do_test where-1.33.5  {
  count {SELECT w FROM t1 WHERE w==97 AND w==97}
} {97 3}
do_test where-1.34 {
  count {SELECT w FROM t1 WHERE w+1==98}
} {97 101}
do_test where-1.35 {
  count {SELECT w FROM t1 WHERE w<3}
} {1 2 5}
do_test where-1.36 {
  count {SELECT w FROM t1 WHERE w<=3}
} {1 2 3 7}
do_test where-1.37 {
  count {SELECT w FROM t1 WHERE w+1<=4 ORDER BY w}
} {1 2 3 201}

do_test where-1.38 {
  count {SELECT (w) FROM t1 WHERE (w)>(97)}
} {98 99 100 7}
do_test where-1.39 {
  count {SELECT (w) FROM t1 WHERE (w)>=(97)}
} {97 98 99 100 9}
do_test where-1.40 {
  count {SELECT (w) FROM t1 WHERE (w)==(97)}
} {97 3}
do_test where-1.41 {
  count {SELECT (w) FROM t1 WHERE ((w)+(1))==(98)}
} {97 101}


# Do the same kind of thing except use a join as the data source.
#
do_test where-2.1 {
  count {
    SELECT w, p FROM t2, t1
................................................................................
# Lets do a 3-way join.
#
do_test where-3.1 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE C.w=101-B.p AND B.r=10202-A.y AND A.w=11
  }
} {11 90 11 9}
do_test where-3.2 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE C.w=101-B.p AND B.r=10202-A.y AND A.w=12
  }
} {12 89 12 9}
do_test where-3.3 {
  count {
    SELECT A.w, B.p, C.w FROM t1 as A, t2 as B, t1 as C
    WHERE A.w=15 AND B.p=C.w AND B.r=10202-A.y
  }
} {15 86 86 9}

# Test to see that the special case of a constant WHERE clause is
# handled.
#
do_test where-4.1 {
  count {
    SELECT * FROM t1 WHERE 0
  }
} {0}
do_test where-4.2 {
  count {
    SELECT * FROM t1 WHERE 1 LIMIT 1
  }
} {1 0 4 1}
do_test where-4.3 {
  execsql {
    SELECT 99 WHERE 0
  }
} {}
do_test where-4.4 {
  execsql {
................................................................................
# Omit these tests if the build is not capable of sub-queries.
#
ifcapable subquery {
  do_test where-5.1 {
    count {
      SELECT * FROM t1 WHERE rowid IN (1,2,3,1234) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 7}
  do_test where-5.2 {
    count {
      SELECT * FROM t1 WHERE rowid+0 IN (1,2,3,1234) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 201}
  do_test where-5.3 {
    count {
      SELECT * FROM t1 WHERE w IN (-1,1,2,3) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 10}
  do_test where-5.4 {
    count {
      SELECT * FROM t1 WHERE w+0 IN (-1,1,2,3) order by 1;
    }
  } {1 0 4 2 1 9 3 1 16 201}
  do_test where-5.5 {
    count {
      SELECT * FROM t1 WHERE rowid IN 
         (select rowid from t1 where rowid IN (-1,2,4))
      ORDER BY 1;
    }
  } {2 1 9 4 2 25 9}
  do_test where-5.6 {
    count {
      SELECT * FROM t1 WHERE rowid+0 IN 
         (select rowid from t1 where rowid IN (-1,2,4))
      ORDER BY 1;
    }
  } {2 1 9 4 2 25 206}
  do_test where-5.7 {
    count {
      SELECT * FROM t1 WHERE w IN 
         (select rowid from t1 where rowid IN (-1,2,4))
      ORDER BY 1;
    }
  } {2 1 9 4 2 25 11}
  do_test where-5.8 {
    count {
      SELECT * FROM t1 WHERE w+0 IN 
         (select rowid from t1 where rowid IN (-1,2,4))
      ORDER BY 1;
    }
  } {2 1 9 4 2 25 206}
  do_test where-5.9 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) ORDER BY 1;
    }
  } {2 1 9 3 1 16 6}
  do_test where-5.10 {
    count {
      SELECT * FROM t1 WHERE x+0 IN (1,7) ORDER BY 1;
    }
  } {2 1 9 3 1 16 201}
  do_test where-5.11 {
    count {
      SELECT * FROM t1 WHERE y IN (6400,8100) ORDER BY 1;
    }
  } {79 6 6400 89 6 8100 201}
  do_test where-5.12 {
    count {
      SELECT * FROM t1 WHERE x=6 AND y IN (6400,8100) ORDER BY 1;
    }
  } {79 6 6400 89 6 8100 6}
  do_test where-5.13 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) AND y NOT IN (6400,8100) ORDER BY 1;
    }
  } {2 1 9 3 1 16 6}
  do_test where-5.14 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) AND y IN (9,10) ORDER BY 1;
    }
  } {2 1 9 6}
  do_test where-5.15 {
    count {
      SELECT * FROM t1 WHERE x IN (1,7) AND y IN (9,16) ORDER BY 1;
    }
  } {2 1 9 3 1 16 8}
}

# This procedure executes the SQL.  Then it checks to see if the OP_Sort
# opcode was executed.  If an OP_Sort did occur, then "sort" is appended
# to the result.  If no OP_Sort happened, then "nosort" is appended.
#
# This procedure is used to check to make sure sorting is or is not
................................................................................
  }
} {1 100 4 2 99 9 3 98 16 sort}
do_test where-6.4 {
  cksort {
    SELECT * FROM t3 WHERE a<10 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

do_test where-6.5 {
  cksort {
    SELECT * FROM t3 WHERE a>0 AND a<10 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}
do_test where-6.6 {
  cksort {
    SELECT * FROM t3 WHERE a>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 nosort}

do_test where-6.7 {
  # UPDATE: src4 does a sort here. It picks a different index because it
  # does not support the covering index optimization.
  cksort {
    SELECT * FROM t3 WHERE b>0 ORDER BY a LIMIT 3
  }
} {1 100 4 2 99 9 3 98 16 sort}

ifcapable subquery {
  do_test where-6.8 {
    cksort {
      SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a LIMIT 3
    }
  } {1 100 4 2 99 9 3 98 16 sort}
}
................................................................................
} {1 100 4 nosort}
do_test where-6.9.6 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY c DESC LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.7 {
  # UPDATE: src4 uses t3acb here. So does not require an external sort.
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY c,a LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.8 {
  cksort {
    SELECT * FROM t3 WHERE a=1 AND c>0 ORDER BY a DESC, c ASC LIMIT 3
  }
} {1 100 4 nosort}
do_test where-6.9.9 {
  cksort {
................................................................................
  }
} {4 9 16 nosort}
do_test where-6.20 {
  cksort {
    SELECT y FROM t1 ORDER BY rowid LIMIT 3;
  }
} {4 9 16 nosort}

do_test where-6.21 {
  cksort {
    SELECT y FROM t1 ORDER BY rowid, y LIMIT 3;
  }
} {4 9 16 nosort}

do_test where-6.22 {
  cksort {
    SELECT y FROM t1 ORDER BY rowid, y DESC LIMIT 3;
  }
} {4 9 16 nosort}
do_test where-6.23 {
  cksort {
................................................................................
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.a, x.b DESC
  } 
} {1/1 1/4 4/1 4/4 nosort}
do_test where-14.5 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, x.a||x.b
  } 
} {4/1 4/4 1/1 1/4 sort}
do_test where-14.6 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, x.a||x.b DESC
  } 
} {4/1 4/4 1/1 1/4 sort}
do_test where-14.7 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, y.a||y.b
  } 
} {4/1 4/4 1/1 1/4 sort}
do_test where-14.7.1 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, x.a, y.a||y.b
  } 
} {4/1 4/4 1/1 1/4 sort}

do_test where-14.7.2 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, x.a, x.a||x.b
  } 
} {4/1 4/4 1/1 1/4 nosort}

do_test where-14.8 {
  cksort {
    SELECT x.a || '/' || y.a FROM t8 x, t8 y ORDER BY x.b, y.a||y.b DESC
  } 
} {4/4 4/1 1/4 1/1 sort}
do_test where-14.9 {
  cksort {