** all members of the RHS set, skipping duplicates.
**
** A cursor is opened on the b-tree object that the RHS of the IN operator
** and pX->iTable is set to the index of that cursor.
**
** The returned value of this function indicates the b-tree type, as follows:
**
**   IN_INDEX_ROWID      - The cursor was opened on a database table.

**   IN_INDEX_INDEX_ASC  - The cursor was opened on an ascending index.
**   IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
**   IN_INDEX_EPH        - The cursor was opened on a specially created and
**                         populated epheremal table.
**
** An existing b-tree might be used if the RHS expression pX is a simple
** subquery such as:
................................................................................
**     SELECT <column> FROM <table>
**
** If the RHS of the IN operator is a list or a more complex subquery, then
** an ephemeral table might need to be generated from the RHS and then
** pX->iTable made to point to the ephermeral table instead of an
** existing table.  
**



** If the prNotFound parameter is 0, then the b-tree will be used to iterate
** through the set members, skipping any duplicates. In this case an
** epheremal table must be used unless the selected <column> is guaranteed
** to be unique - either because it is an INTEGER PRIMARY KEY or it
** has a UNIQUE constraint or UNIQUE index.


















**
** If the prNotFound parameter is not 0, then the b-tree will be used 
** for fast set membership tests. In this case an epheremal table must 
** be used unless <column> is an INTEGER PRIMARY KEY or an index can 
** be found with <column> as its left-most column.
**
** When the b-tree is being used for membership tests, the calling function

** all members of the RHS set, skipping duplicates.
**
** A cursor is opened on the b-tree object that the RHS of the IN operator
** and pX->iTable is set to the index of that cursor.
**
** The returned value of this function indicates the b-tree type, as follows:
**
**   IN_INDEX_ROWID      - The cursor was opened on the PK index of a
**                         table with an implicit integer primary key.
**   IN_INDEX_INDEX_ASC  - The cursor was opened on an ascending index.
**   IN_INDEX_INDEX_DESC - The cursor was opened on a descending index.
**   IN_INDEX_EPH        - The cursor was opened on a specially created and
**                         populated epheremal table.
**
** An existing b-tree might be used if the RHS expression pX is a simple
** subquery such as:
................................................................................
**     SELECT <column> FROM <table>
**
** If the RHS of the IN operator is a list or a more complex subquery, then
** an ephemeral table might need to be generated from the RHS and then
** pX->iTable made to point to the ephermeral table instead of an
** existing table.  
**
**
** ITERATING THROUGH SET MEMBERS
** 
**   If the prNotFound parameter is 0, then the b-tree will be used to 
**   iterate through the set members, skipping any duplicates. In this



**   case the piCov parameter is always non-zero. An index on column 
**   <column> of <table> is used in this case if:
**
**     1. The index guarantees the column is unique (i.e. it is a UNIQUE
**        or PRIMARY KEY Index), and
**
**     2. The index uses the same collation sequence as the comparison
**        performed by expression pX.
**
**     3. The index is a covering index for <column> (either because it
**        is a PRIMARY KEY or was created with a COVERING clause).
**
**   Restriction (3) could be removed by the calling code in where.c.
**
**   Before returning, *piCov is set to the column number of <column> in
**   the value associated with the selected covering or primary key index.
**
** SET MEMBERSHIP TESTS
**
** If the prNotFound parameter is not 0, then the b-tree will be used 
** for fast set membership tests. In this case an epheremal table must 
** be used unless <column> is an INTEGER PRIMARY KEY or an index can 
** be found with <column> as its left-most column.
**
** When the b-tree is being used for membership tests, the calling function

** the rowids returned by a WHERE clause.  Return FALSE if doing an
** UPDATE or DELETE might change subsequent WHERE clause results.
*/
int sqlite4WhereOkOnePass(WhereInfo *pWInfo){
  return pWInfo->okOnePass;
}


/*
** Move the content of pSrc into pDest
*/
static void whereOrMove(WhereOrSet *pDest, WhereOrSet *pSrc){
  pDest->n = pSrc->n;
  memcpy(pDest->a, pSrc->a, pDest->n*sizeof(pDest->a[0]));
}
................................................................................
  }
}


/*
** Skip over any TK_COLLATE and/or TK_AS operators at the root of
** an expression.





*/
Expr *sqlite4ExprSkipCollate(Expr *pExpr){


  while( pExpr && (pExpr->op==TK_COLLATE || pExpr->op==TK_AS) ){
    pExpr = pExpr->pLeft;
  }
  return pExpr;
}

/*
................................................................................
        }
      }else{
        const char *zCover = (flags & WHERE_IDX_ONLY) ? " COVERING" : "";
        zMsg = sqlite4MAppendf(db, zMsg, "%s USING%s INDEX %s%s",
            zMsg, zCover, pIdx->zName, zWhere
        );
      }

      sqlite4DbFree(db, zWhere);
#if 0
    }else if( (flags & WHERE_IPK)!=0 && (flags & WHERE_CONSTRAINT)!=0 ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s USING INTEGER PRIMARY KEY", zMsg);

      if( flags&(WHERE_COLUMN_EQ|WHERE_COLUMN_IN) ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid=?)", zMsg);
      }else if( (flags&WHERE_BOTH_LIMIT)==WHERE_BOTH_LIMIT ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid>? AND rowid<?)", zMsg);
      }else if( flags&WHERE_BTM_LIMIT ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid>?)", zMsg);
      }else if( ALWAYS(flags&WHERE_TOP_LIMIT) ){
        zMsg = sqlite4MAppendf(db, zMsg, "%s (rowid<?)", zMsg);
      }
#endif
    }
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    else if( (flags & WHERE_VIRTUALTABLE)!=0 ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,
                  pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr);
    }
#endif
................................................................................
    pLevel->p1 = iCur;
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
    sqlite4ReleaseTempRange(pParse, iReg, nConstraint+2);
    sqlite4ExprCachePop(pParse, 1);
  }else
#endif /* SQLITE4_OMIT_VIRTUALTABLE */

#if 0
  if( (pLoop->wsFlags & WHERE_IPK)!=0
   && (pLoop->wsFlags & (WHERE_COLUMN_IN|WHERE_COLUMN_EQ))!=0
  ){
    assert( 0 );

    /* Case 2:  We can directly reference a single row using an
    **          equality comparison against the ROWID field.  Or
    **          we reference multiple rows using a "rowid IN (...)"
    **          construct.
    */
    assert( pLoop->u.btree.nEq==1 );
    iReleaseReg = sqlite4GetTempReg(pParse);
    pTerm = pLoop->aLTerm[0];
    assert( pTerm!=0 );
    assert( pTerm->pExpr!=0 );
    assert( omitTable==0 );
    testcase( pTerm->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
    iRowidReg = codeEqualityTerm(pParse, pTerm, pLevel, 0, bRev, iReleaseReg);
    addrNxt = pLevel->addrNxt;
    sqlite4VdbeAddOp2(v, OP_MustBeInt, iRowidReg, addrNxt);
    sqlite4VdbeAddOp3(v, OP_NotExists, iCur, addrNxt, iRowidReg);
    sqlite4ExprCacheAffinityChange(pParse, iRowidReg, 1);
    sqlite4ExprCacheStore(pParse, iCur, -1, iRowidReg);
    VdbeComment((v, "pk"));
    pLevel->op = OP_Noop;
  }else if( (pLoop->wsFlags & WHERE_IPK)!=0
         && (pLoop->wsFlags & WHERE_COLUMN_RANGE)!=0
  ){
    /* Case 3:  We have an inequality comparison against the ROWID field.
    */
    int testOp = OP_Noop;
    int start;
    int memEndValue = 0;
    WhereTerm *pStart, *pEnd;

    assert( 0 );

    assert( omitTable==0 );
    j = 0;
    pStart = pEnd = 0;
    if( pLoop->wsFlags & WHERE_BTM_LIMIT ) pStart = pLoop->aLTerm[j++];
    if( pLoop->wsFlags & WHERE_TOP_LIMIT ) pEnd = pLoop->aLTerm[j++];
    assert( pStart!=0 || pEnd!=0 );
    if( bRev ){
      pTerm = pStart;
      pStart = pEnd;
      pEnd = pTerm;
    }
    if( pStart ){
      Expr *pX;             /* The expression that defines the start bound */
      int r1, rTemp;        /* Registers for holding the start boundary */

      /* The following constant maps TK_xx codes into corresponding 
      ** seek opcodes.  It depends on a particular ordering of TK_xx
      */
      const u8 aMoveOp[] = {
           /* TK_GT */  OP_SeekGt,
           /* TK_LE */  OP_SeekLe,
           /* TK_LT */  OP_SeekLt,
           /* TK_GE */  OP_SeekGe
      };
      assert( TK_LE==TK_GT+1 );      /* Make sure the ordering.. */
      assert( TK_LT==TK_GT+2 );      /*  ... of the TK_xx values... */
      assert( TK_GE==TK_GT+3 );      /*  ... is correcct. */

      assert( (pStart->wtFlags & TERM_VNULL)==0 );
      testcase( pStart->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
      pX = pStart->pExpr;
      assert( pX!=0 );
      testcase( pStart->leftCursor!=iCur ); /* transitive constraints */
      r1 = sqlite4ExprCodeTemp(pParse, pX->pRight, &rTemp);
      sqlite4VdbeAddOp3(v, aMoveOp[pX->op-TK_GT], iCur, addrBrk, r1);
      VdbeComment((v, "pk"));
      sqlite4ExprCacheAffinityChange(pParse, r1, 1);
      sqlite4ReleaseTempReg(pParse, rTemp);
      disableTerm(pLevel, pStart);
    }else{
      sqlite4VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, addrBrk);
    }
    if( pEnd ){
      Expr *pX;
      pX = pEnd->pExpr;
      assert( pX!=0 );
      assert( (pEnd->wtFlags & TERM_VNULL)==0 );
      testcase( pEnd->leftCursor!=iCur ); /* Transitive constraints */
      testcase( pEnd->wtFlags & TERM_VIRTUAL ); /* EV: R-30575-11662 */
      memEndValue = ++pParse->nMem;
      sqlite4ExprCode(pParse, pX->pRight, memEndValue);
      if( pX->op==TK_LT || pX->op==TK_GT ){
        testOp = bRev ? OP_Le : OP_Ge;
      }else{
        testOp = bRev ? OP_Lt : OP_Gt;
      }
      disableTerm(pLevel, pEnd);
    }
    start = sqlite4VdbeCurrentAddr(v);
    pLevel->op = bRev ? OP_Prev : OP_Next;
    pLevel->p1 = iCur;
    pLevel->p2 = start;
    assert( pLevel->p5==0 );
    if( testOp!=OP_Noop ){
      iRowidReg = iReleaseReg = sqlite4GetTempReg(pParse);
      sqlite4VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg);
      sqlite4ExprCacheStore(pParse, iCur, -1, iRowidReg);
      sqlite4VdbeAddOp3(v, testOp, memEndValue, addrBrk, iRowidReg);
      sqlite4VdbeChangeP5(v, SQLITE4_AFF_NUMERIC | SQLITE4_JUMPIFNULL);
    }
  }else 
#endif
  if( pLoop->wsFlags & WHERE_INDEXED ){
    /* Case 4: A scan using an index.
    **
    **         The WHERE clause may contain zero or more equality 
    **         terms ("==" or "IN" operators) that refer to the N
    **         left-most columns of the index. It may also contain
    **         inequality constraints (>, <, >= or <=) on the indexed
................................................................................
        }
        /* Loop through table entries that match term pOrTerm. */
        pSubWInfo = sqlite4WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
                        WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
                        WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY, iCovCur);
        assert( pSubWInfo || pParse->nErr || pParse->db->mallocFailed );
        if( pSubWInfo ){

          explainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
          );
          if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
            sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);
            sqlite4VdbeAddOp4Int(v, OP_RowSetTest, regKeyset,
................................................................................
          ** If the call to sqlite4WhereBegin() above resulted in a scan that
          ** uses an index, and this is either the first OR-connected term
          ** processed or the index is the same as that used by all previous
          ** terms, set pCov to the candidate covering index. Otherwise, set 
          ** pCov to NULL to indicate that no candidate covering index will 
          ** be available.
          */
#if 0
          pSubLoop = pSubWInfo->a[0].pWLoop;
          assert( (pSubLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
          if( (pSubLoop->wsFlags & WHERE_INDEXED)!=0
           && (ii==0 || pSubLoop->u.btree.pIndex==pCov)
          ){
            assert( pSubWInfo->a[0].iIdxCur==iCovCur );
            pCov = pSubLoop->u.btree.pIndex;



          }else{
            pCov = 0;
          }
#endif

          /* Finish the loop through table entries that match term pOrTerm. */
          sqlite4WhereEnd(pSubWInfo);
        }
      }
    }
    pLevel->u.pCovidx = pCov;

    if( pCov ) pLevel->iIdxCur = iCovCur;


    if( pAndExpr ){
      pAndExpr->pLeft = 0;
      sqlite4ExprDelete(pParse->db, pAndExpr);
    }
    sqlite4VdbeChangeP1(v, iRetInit, sqlite4VdbeCurrentAddr(v));
    sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
    sqlite4VdbeResolveLabel(v, iLoopBody);
................................................................................

    if( pWInfo->nLevel>1 ) sqlite4StackFree(pParse->db, pOrTab);
    if( !untestedTerms ) disableTerm(pLevel, pTerm);
  }else
#endif /* SQLITE4_OMIT_OR_OPTIMIZATION */

  {
    /* TODO: This case is currently being used. Why can't it use the 
    ** index case instead? */ 

    /* Case 6:  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);
................................................................................
     && (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0 
    ){
      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
      WhereTerm *pOrTerm;
      int once = 1;
      int i, j;

      pItem = pWInfo->pTabList->a + pNew->iTab;
      iCur = pItem->iCursor;
      sSubBuild = *pBuilder;
      sSubBuild.pOrderBy = 0;
      sSubBuild.pOrSet = &sCur;

      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
................................................................................
          tempWC.op = TK_AND;
          tempWC.nTerm = 1;
          tempWC.a = pOrTerm;
          sSubBuild.pWC = &tempWC;
        }else{
          continue;
        }

        sCur.n = 0;
#ifndef SQLITE4_OMIT_VIRTUALTABLE
        if( IsVirtual(pItem->pTab) ){
          rc = whereLoopAddVirtual(&sSubBuild);
          for(i=0; i<sCur.n; i++) sCur.a[i].prereq |= mExtra;
        }else
#endif
        {
          rc = whereLoopAddBtree(&sSubBuild, mExtra);
        }

        assert( rc==SQLITE4_OK || sCur.n==0 );
        if( sCur.n==0 ){
          sSum.n = 0;
          break;
        }else if( once ){
          whereOrMove(&sSum, &sCur);
          once = 0;
        }else{
          whereOrMove(&sPrev, &sSum);
          sSum.n = 0;
          for(i=0; i<sPrev.n; i++){
            for(j=0; j<sCur.n; j++){
              whereOrInsert(&sSum, sPrev.a[i].prereq | sCur.a[j].prereq,
                  whereCostAdd(sPrev.a[i].rRun, sCur.a[j].rRun),
                  whereCostAdd(sPrev.a[i].nOut, sCur.a[j].nOut));
            }
          }
        }
      }
      pNew->nLTerm = 1;
      pNew->aLTerm[0] = pTerm;
      pNew->wsFlags = WHERE_MULTI_OR;
................................................................................
        pNew->prereq = sSum.a[i].prereq;
        rc = whereLoopInsert(pBuilder, pNew);
      }
    }
  }
  return rc;
}


/*
** Add all WhereLoop objects for all tables 
*/
static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
  WhereInfo *pWInfo = pBuilder->pWInfo;
  Bitmask mExtra = 0;
................................................................................
        if( sqlite4_stricmp(z1, z2)!=0 ) continue;
      }
      obSat |= MASKBIT(i);
    }

    if( (pLoop->wsFlags & WHERE_ONEROW)==0 ){
      Index *pPk = 0;
#if 0
      if( pLoop->wsFlags & WHERE_IPK ){
        pIndex = 0;
        nColumn = 0;
      }else 
#endif
      if( (pIndex = pLoop->u.btree.pIndex)==0 || pIndex->bUnordered ){
        return 0;
      }else{
        isOrderDistinct = pIndex->onError!=OE_None;
        pPk = sqlite4FindPrimaryKey(pIndex->pTable, 0);
        nColumn = idxColumnCount(pIndex, pPk);
      }
................................................................................
#endif
    if( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
         && (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 ){
      int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
      sqlite4OpenPrimaryKey(pParse, pTabItem->iCursor, iDb, pTab, op);
      testcase( !pWInfo->okOnePass && pTab->nCol==BMS-1 );
      testcase( !pWInfo->okOnePass && pTab->nCol==BMS );
#if 0
      if( !pWInfo->okOnePass && pTab->nCol<BMS ){
        Bitmask b = pTabItem->colUsed;
        int n = 0;
        for(; b; b=b>>1, n++){}
        sqlite4VdbeChangeP4(v, sqlite4VdbeCurrentAddr(v)-1, 
                            SQLITE4_INT_TO_PTR(n), P4_INT32);
        assert( n<=pTab->nCol );
      }
#endif
    }
#if 0
    else{
      sqlite4TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
    }
#endif
#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
    if( (pLoop->wsFlags & WHERE_AUTO_INDEX)!=0 ){
      constructAutomaticIndex(pParse, &pWInfo->sWC, pTabItem, notReady, pLevel);
    }else
#endif
    if( pLoop->wsFlags & WHERE_INDEXED ){
      Index *pIx = pLoop->u.btree.pIndex;

** the rowids returned by a WHERE clause.  Return FALSE if doing an
** UPDATE or DELETE might change subsequent WHERE clause results.
*/
int sqlite4WhereOkOnePass(WhereInfo *pWInfo){
  return pWInfo->okOnePass;
}


/*
** Move the content of pSrc into pDest
*/
static void whereOrMove(WhereOrSet *pDest, WhereOrSet *pSrc){
  pDest->n = pSrc->n;
  memcpy(pDest->a, pSrc->a, pDest->n*sizeof(pDest->a[0]));
}
................................................................................
  }
}


/*
** Skip over any TK_COLLATE and/or TK_AS operators at the root of
** an expression.
**
** NOTE: This function was added when the NGQP was imported from SQLite3.
** At present it is not actually possible for Expr.op to be set to 
** TK_COLLATE. But will be if the way Expr objects represent collation
** sequences is changed to match SQLite3.
*/
static Expr *sqlite4ExprSkipCollate(Expr *pExpr){
  assert( pExpr==0 || pExpr->op!=TK_COLLATE );

  while( pExpr && (pExpr->op==TK_COLLATE || pExpr->op==TK_AS) ){
    pExpr = pExpr->pLeft;
  }
  return pExpr;
}

/*
................................................................................
        }
      }else{
        const char *zCover = (flags & WHERE_IDX_ONLY) ? " COVERING" : "";
        zMsg = sqlite4MAppendf(db, zMsg, "%s USING%s INDEX %s%s",
            zMsg, zCover, pIdx->zName, zWhere
        );
      }

      sqlite4DbFree(db, zWhere);














    }
#ifndef SQLITE4_OMIT_VIRTUALTABLE
    else if( (flags & WHERE_VIRTUALTABLE)!=0 ){
      zMsg = sqlite4MAppendf(db, zMsg, "%s VIRTUAL TABLE INDEX %d:%s", zMsg,
                  pLoop->u.vtab.idxNum, pLoop->u.vtab.idxStr);
    }
#endif
................................................................................
    pLevel->p1 = iCur;
    pLevel->p2 = sqlite4VdbeCurrentAddr(v);
    sqlite4ReleaseTempRange(pParse, iReg, nConstraint+2);
    sqlite4ExprCachePop(pParse, 1);
  }else
#endif /* SQLITE4_OMIT_VIRTUALTABLE */















































































































  if( pLoop->wsFlags & WHERE_INDEXED ){
    /* Case 4: A scan using an index.
    **
    **         The WHERE clause may contain zero or more equality 
    **         terms ("==" or "IN" operators) that refer to the N
    **         left-most columns of the index. It may also contain
    **         inequality constraints (>, <, >= or <=) on the indexed
................................................................................
        }
        /* Loop through table entries that match term pOrTerm. */
        pSubWInfo = sqlite4WhereBegin(pParse, pOrTab, pOrExpr, 0, 0,
                        WHERE_OMIT_OPEN_CLOSE | WHERE_AND_ONLY |
                        WHERE_FORCE_TABLE | WHERE_ONETABLE_ONLY, iCovCur);
        assert( pSubWInfo || pParse->nErr || pParse->db->mallocFailed );
        if( pSubWInfo ){
          WhereLoop *pSubLoop;
          explainOneScan(
              pParse, pOrTab, &pSubWInfo->a[0], iLevel, pLevel->iFrom, 0
          );
          if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
            int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
            sqlite4VdbeAddOp2(v, OP_RowKey, iCur, regKey);
            sqlite4VdbeAddOp4Int(v, OP_RowSetTest, regKeyset,
................................................................................
          ** If the call to sqlite4WhereBegin() above resulted in a scan that
          ** uses an index, and this is either the first OR-connected term
          ** processed or the index is the same as that used by all previous
          ** terms, set pCov to the candidate covering index. Otherwise, set 
          ** pCov to NULL to indicate that no candidate covering index will 
          ** be available.
          */

          pSubLoop = pSubWInfo->a[0].pWLoop;
          assert( (pSubLoop->wsFlags & WHERE_AUTO_INDEX)==0 );
          if( (pSubLoop->wsFlags & WHERE_INDEXED)!=0
           && (ii==0 || pSubLoop->u.btree.pIndex==pCov)
          ){

            pCov = pSubLoop->u.btree.pIndex;
            assert( pCov->eIndexType==SQLITE4_INDEX_PRIMARYKEY 
                 || pSubWInfo->a[0].iIdxCur==iCovCur 
            );
          }else{
            pCov = 0;
          }


          /* Finish the loop through table entries that match term pOrTerm. */
          sqlite4WhereEnd(pSubWInfo);
        }
      }
    }
    assert( pLevel->u.pCovidx==0 );
    if( pCov && pCov->eIndexType!=SQLITE4_INDEX_PRIMARYKEY ){
      pLevel->iIdxCur = iCovCur;
      pLevel->u.pCovidx = pCov;
    }
    if( pAndExpr ){
      pAndExpr->pLeft = 0;
      sqlite4ExprDelete(pParse->db, pAndExpr);
    }
    sqlite4VdbeChangeP1(v, iRetInit, sqlite4VdbeCurrentAddr(v));
    sqlite4VdbeAddOp2(v, OP_Goto, 0, pLevel->addrBrk);
    sqlite4VdbeResolveLabel(v, iLoopBody);
................................................................................

    if( pWInfo->nLevel>1 ) sqlite4StackFree(pParse->db, pOrTab);
    if( !untestedTerms ) disableTerm(pLevel, pTerm);
  }else
#endif /* SQLITE4_OMIT_OR_OPTIMIZATION */

  {



    /* Case 6:  There is no usable index.  We must do a complete
    **          scan of the entire table. This comes up when scanning
    **          through b-trees containing materialized sub-queries or 
    **          views.
    */
    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);
................................................................................
     && (pTerm->u.pOrInfo->indexable & pNew->maskSelf)!=0 
    ){
      WhereClause * const pOrWC = &pTerm->u.pOrInfo->wc;
      WhereTerm * const pOrWCEnd = &pOrWC->a[pOrWC->nTerm];
      WhereTerm *pOrTerm;
      int once = 1;
      int i, j;
    
      pItem = pWInfo->pTabList->a + pNew->iTab;
      iCur = pItem->iCursor;
      sSubBuild = *pBuilder;
      sSubBuild.pOrderBy = 0;
      sSubBuild.pOrSet = &sCur;

      for(pOrTerm=pOrWC->a; pOrTerm<pOrWCEnd; pOrTerm++){
................................................................................
          tempWC.op = TK_AND;
          tempWC.nTerm = 1;
          tempWC.a = pOrTerm;
          sSubBuild.pWC = &tempWC;
        }else{
          continue;
        }

        sCur.n = 0;
#ifndef SQLITE4_OMIT_VIRTUALTABLE
        if( IsVirtual(pItem->pTab) ){
          rc = whereLoopAddVirtual(&sSubBuild);
          for(i=0; i<sCur.n; i++) sCur.a[i].prereq |= mExtra;
        }else
#endif
        {
          rc = whereLoopAddBtree(&sSubBuild, mExtra);
        }

        assert( rc==SQLITE4_OK || sCur.n==0 );
        if( sCur.n==0 ){
          sSum.n = 0;
          break;
        }else if( once ){
          whereOrMove(&sSum, &sCur);
          once = 0;
        }else{
          whereOrMove(&sPrev, &sSum);
          sSum.n = 0;
          for(i=0; i<sPrev.n; i++){
            for(j=0; j<sCur.n; j++){
              whereOrInsert(&sSum, sPrev.a[i].prereq | sCur.a[j].prereq,
                            whereCostAdd(sPrev.a[i].rRun, sCur.a[j].rRun),
                            whereCostAdd(sPrev.a[i].nOut, sCur.a[j].nOut));
            }
          }
        }
      }
      pNew->nLTerm = 1;
      pNew->aLTerm[0] = pTerm;
      pNew->wsFlags = WHERE_MULTI_OR;
................................................................................
        pNew->prereq = sSum.a[i].prereq;
        rc = whereLoopInsert(pBuilder, pNew);
      }
    }
  }
  return rc;
}


/*
** Add all WhereLoop objects for all tables 
*/
static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
  WhereInfo *pWInfo = pBuilder->pWInfo;
  Bitmask mExtra = 0;
................................................................................
        if( sqlite4_stricmp(z1, z2)!=0 ) continue;
      }
      obSat |= MASKBIT(i);
    }

    if( (pLoop->wsFlags & WHERE_ONEROW)==0 ){
      Index *pPk = 0;






      if( (pIndex = pLoop->u.btree.pIndex)==0 || pIndex->bUnordered ){
        return 0;
      }else{
        isOrderDistinct = pIndex->onError!=OE_None;
        pPk = sqlite4FindPrimaryKey(pIndex->pTable, 0);
        nColumn = idxColumnCount(pIndex, pPk);
      }
................................................................................
#endif
    if( (pLoop->wsFlags & WHERE_IDX_ONLY)==0
         && (wctrlFlags & WHERE_OMIT_OPEN_CLOSE)==0 ){
      int op = pWInfo->okOnePass ? OP_OpenWrite : OP_OpenRead;
      sqlite4OpenPrimaryKey(pParse, pTabItem->iCursor, iDb, pTab, op);
      testcase( !pWInfo->okOnePass && pTab->nCol==BMS-1 );
      testcase( !pWInfo->okOnePass && pTab->nCol==BMS );








    }







#ifndef SQLITE4_OMIT_AUTOMATIC_INDEX
    if( (pLoop->wsFlags & WHERE_AUTO_INDEX)!=0 ){
      constructAutomaticIndex(pParse, &pWInfo->sWC, pTabItem, notReady, pLevel);
    }else
#endif
    if( pLoop->wsFlags & WHERE_INDEXED ){
      Index *pIx = pLoop->u.btree.pIndex;