Fossil

**
** See also: [sqlite3_libversion()],
** [sqlite3_libversion_number()], [sqlite3_sourceid()],
** [sqlite_version()] and [sqlite_source_id()].
*/
#define SQLITE_VERSION        "3.7.15"
#define SQLITE_VERSION_NUMBER 3007015
#define SQLITE_SOURCE_ID      "2012-12-08 22:14:29 92c9ab56b1c67b9468bec57ab1d2c483a69a2810"

/*
** CAPI3REF: Run-Time Library Version Numbers
** KEYWORDS: sqlite3_version, sqlite3_sourceid
**
** These interfaces provide the same information as the [SQLITE_VERSION],
** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros

** VFS has handled the PRAGMA itself and the parser generates a no-op
** prepared statement.  ^If the [SQLITE_FCNTL_PRAGMA] file control returns
** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
** that the VFS encountered an error while handling the [PRAGMA] and the
** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
** file control occurs at the beginning of pragma statement analysis and so
** it is able to override built-in [PRAGMA] statements.

**
** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
** ^This file-control may be invoked by SQLite on the database file handle
** shortly after it is opened in order to provide a custom VFS with access
** to the connections busy-handler callback. The argument is of type (void **)
** - an array of two (void *) values. The first (void *) actually points
** to a function of type (int (*)(void *)). In order to invoke the connections
** busy-handler, this function should be invoked with the second (void *) in
** the array as the only argument. If it returns non-zero, then the operation
** should be retried. If it returns zero, the custom VFS should abandon the
** current operation.
**
** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
** ^Application can invoke this file-control to have SQLite generate a
** temporary filename using the same algorithm that is followed to generate
** temporary filenames for TEMP tables and other internal uses.  The
** argument should be a char** which will be filled with the filename
** written into memory obtained from [sqlite3_malloc()].  The caller should
** invoke [sqlite3_free()] on the result to avoid a memory leak.
**
** </ul>
*/
#define SQLITE_FCNTL_LOCKSTATE               1
#define SQLITE_GET_LOCKPROXYFILE             2
#define SQLITE_SET_LOCKPROXYFILE             3
#define SQLITE_LAST_ERRNO                    4
#define SQLITE_FCNTL_SIZE_HINT               5
#define SQLITE_FCNTL_CHUNK_SIZE              6
#define SQLITE_FCNTL_FILE_POINTER            7
#define SQLITE_FCNTL_SYNC_OMITTED            8
#define SQLITE_FCNTL_WIN32_AV_RETRY          9
#define SQLITE_FCNTL_PERSIST_WAL            10
#define SQLITE_FCNTL_OVERWRITE              11
#define SQLITE_FCNTL_VFSNAME                12
#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
#define SQLITE_FCNTL_PRAGMA                 14
#define SQLITE_FCNTL_BUSYHANDLER            15
#define SQLITE_FCNTL_TEMPFILENAME           16

/*
** CAPI3REF: Mutex Handle
**
** The mutex module within SQLite defines [sqlite3_mutex] to be an
** abstract type for a mutex object.  The SQLite core never looks
** at the internal representation of an [sqlite3_mutex].  It only

#define COLFLAG_HIDDEN   0x0002    /* A hidden column in a virtual table */

/*
** A "Collating Sequence" is defined by an instance of the following
** structure. Conceptually, a collating sequence consists of a name and
** a comparison routine that defines the order of that sequence.
**












** If CollSeq.xCmp is NULL, it means that the
** collating sequence is undefined.  Indices built on an undefined
** collating sequence may not be read or written.
*/
struct CollSeq {
  char *zName;          /* Name of the collating sequence, UTF-8 encoded */
  u8 enc;               /* Text encoding handled by xCmp() */
  void *pUser;          /* First argument to xCmp() */

  Expr *pLeft;           /* Left subnode */
  Expr *pRight;          /* Right subnode */
  union {
    ExprList *pList;     /* Function arguments or in "<expr> IN (<expr-list)" */
    Select *pSelect;     /* Used for sub-selects and "<expr> IN (<select>)" */
  } x;


  /* If the EP_Reduced flag is set in the Expr.flags mask, then no
  ** space is allocated for the fields below this point. An attempt to
  ** access them will result in a segfault or malfunction.
  *********************************************************************/

#if SQLITE_MAX_EXPR_DEPTH>0

#define EP_Agg        0x0002  /* Contains one or more aggregate functions */
#define EP_Resolved   0x0004  /* IDs have been resolved to COLUMNs */
#define EP_Error      0x0008  /* Expression contains one or more errors */
#define EP_Distinct   0x0010  /* Aggregate function with DISTINCT keyword */
#define EP_VarSelect  0x0020  /* pSelect is correlated, not constant */
#define EP_DblQuoted  0x0040  /* token.z was originally in "..." */
#define EP_InfixFunc  0x0080  /* True for an infix function: LIKE, GLOB, etc */
#define EP_Collate    0x0100  /* Tree contains a TK_COLLATE opeartor */
#define EP_FixedDest  0x0200  /* Result needed in a specific register */
#define EP_IntValue   0x0400  /* Integer value contained in u.iValue */
#define EP_xIsSelect  0x0800  /* x.pSelect is valid (otherwise x.pList is) */
#define EP_Hint       0x1000  /* Not used */
#define EP_Reduced    0x2000  /* Expr struct is EXPR_REDUCEDSIZE bytes only */
#define EP_TokenOnly  0x4000  /* Expr struct is EXPR_TOKENONLYSIZE bytes only */
#define EP_Static     0x8000  /* Held in memory not obtained from malloc() */

#define OPFLAG_APPEND        0x08    /* This is likely to be an append */
#define OPFLAG_USESEEKRESULT 0x10    /* Try to avoid a seek in BtreeInsert() */
#define OPFLAG_CLEARCACHE    0x20    /* Clear pseudo-table cache in OP_Column */
#define OPFLAG_LENGTHARG     0x40    /* OP_Column only used for length() */
#define OPFLAG_TYPEOFARG     0x80    /* OP_Column only used for typeof() */
#define OPFLAG_BULKCSR       0x01    /* OP_Open** used to open bulk cursor */
#define OPFLAG_P2ISREG       0x02    /* P2 to OP_Open** is a register number */
#define OPFLAG_PERMUTE       0x01    /* OP_Compare: use the permutation */

/*
 * Each trigger present in the database schema is stored as an instance of
 * struct Trigger. 
 *
 * Pointers to instances of struct Trigger are stored in two ways.
 * 1. In the "trigHash" hash table (part of the sqlite3* that represents the 

SQLITE_PRIVATE u8 sqlite3HexToInt(int h);
SQLITE_PRIVATE int sqlite3TwoPartName(Parse *, Token *, Token *, Token **);
SQLITE_PRIVATE const char *sqlite3ErrStr(int);
SQLITE_PRIVATE int sqlite3ReadSchema(Parse *pParse);
SQLITE_PRIVATE CollSeq *sqlite3FindCollSeq(sqlite3*,u8 enc, const char*,int);
SQLITE_PRIVATE CollSeq *sqlite3LocateCollSeq(Parse *pParse, const char*zName);
SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr);
SQLITE_PRIVATE Expr *sqlite3ExprAddCollateToken(Parse *pParse, Expr*, Token*);
SQLITE_PRIVATE Expr *sqlite3ExprAddCollateString(Parse*,Expr*,const char*);
SQLITE_PRIVATE Expr *sqlite3ExprSkipCollate(Expr*);
SQLITE_PRIVATE int sqlite3CheckCollSeq(Parse *, CollSeq *);
SQLITE_PRIVATE int sqlite3CheckObjectName(Parse *, const char *);
SQLITE_PRIVATE void sqlite3VdbeSetChanges(sqlite3 *, int);
SQLITE_PRIVATE int sqlite3AddInt64(i64*,i64);
SQLITE_PRIVATE int sqlite3SubInt64(i64*,i64);
SQLITE_PRIVATE int sqlite3MulInt64(i64*,i64);
SQLITE_PRIVATE int sqlite3AbsInt32(int);

  }else if( (*pArg)==0 ){
    pFile->ctrlFlags &= ~mask;
  }else{
    pFile->ctrlFlags |= mask;
  }
}

/* Forward declaration */
static int unixGetTempname(int nBuf, char *zBuf);

/*
** Information and control of an open file handle.
*/
static int unixFileControl(sqlite3_file *id, int op, void *pArg){
  unixFile *pFile = (unixFile*)id;
  switch( op ){
    case SQLITE_FCNTL_LOCKSTATE: {

    case SQLITE_FCNTL_POWERSAFE_OVERWRITE: {
      unixModeBit(pFile, UNIXFILE_PSOW, (int*)pArg);
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_VFSNAME: {
      *(char**)pArg = sqlite3_mprintf("%s", pFile->pVfs->zName);
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_TEMPFILENAME: {
      char *zTFile = sqlite3_malloc( pFile->pVfs->mxPathname );
      if( zTFile ){
        unixGetTempname(pFile->pVfs->mxPathname, zTFile);
        *(char**)pArg = zTFile;
      }
      return SQLITE_OK;
    }
#ifdef SQLITE_DEBUG
    /* The pager calls this method to signal that it has done
    ** a rollback and that the database is therefore unchanged and
    ** it hence it is OK for the transaction change counter to be
    ** unchanged.
    */

  }else if( (*pArg)==0 ){
    pFile->ctrlFlags &= ~mask;
  }else{
    pFile->ctrlFlags |= mask;
  }
}

/* Forward declaration */
static int getTempname(int nBuf, char *zBuf);

/*
** Control and query of the open file handle.
*/
static int winFileControl(sqlite3_file *id, int op, void *pArg){
  winFile *pFile = (winFile*)id;
  switch( op ){
    case SQLITE_FCNTL_LOCKSTATE: {

      }
      if( a[1]>0 ){
        win32IoerrRetryDelay = a[1];
      }else{
        a[1] = win32IoerrRetryDelay;
      }
      return SQLITE_OK;
    }
    case SQLITE_FCNTL_TEMPFILENAME: {
      char *zTFile = sqlite3_malloc( pFile->pVfs->mxPathname );
      if( zTFile ){
        getTempname(pFile->pVfs->mxPathname, zTFile);
        *(char**)pArg = zTFile;
      }
      return SQLITE_OK;
    }
  }
  return SQLITE_NOTFOUND;
}

/*
** Return the sector size in bytes of the underlying block device for

      int i, j;
      KeyInfo *pKeyInfo = pOp->p4.pKeyInfo;
      assert( pKeyInfo->aSortOrder!=0 );
      sqlite3_snprintf(nTemp, zTemp, "keyinfo(%d", pKeyInfo->nField);
      i = sqlite3Strlen30(zTemp);
      for(j=0; j<pKeyInfo->nField; j++){
        CollSeq *pColl = pKeyInfo->aColl[j];
        const char *zColl = pColl ? pColl->zName : "nil";
        int n = sqlite3Strlen30(zColl);
        if( i+n>nTemp-6 ){
          memcpy(&zTemp[i],",...",4);
          break;
        }
        zTemp[i++] = ',';
        if( pKeyInfo->aSortOrder[j] ){
          zTemp[i++] = '-';
        }
        memcpy(&zTemp[i], zColl, n+1);
        i += n;




      }
      zTemp[i++] = ')';
      zTemp[i] = 0;
      assert( i<nTemp );
      break;
    }
    case P4_COLLSEQ: {

#endif

#ifdef SQLITE_DEBUG
/*
** Print the value of a register for tracing purposes:
*/
static void memTracePrint(FILE *out, Mem *p){
  if( p->flags & MEM_Invalid ){
    fprintf(out, " undefined");
  }else if( p->flags & MEM_Null ){
    fprintf(out, " NULL");
  }else if( (p->flags & (MEM_Int|MEM_Str))==(MEM_Int|MEM_Str) ){
    fprintf(out, " si:%lld", p->u.i);
  }else if( p->flags & MEM_Int ){
    fprintf(out, " i:%lld", p->u.i);
#ifndef SQLITE_OMIT_FLOATING_POINT
  }else if( p->flags & MEM_Real ){

  u.ae.n = pOp->p3;
  pIn1 = &aMem[pOp->p1];
  pOut = &aMem[pOp->p2];
  assert( pOut!=pIn1 );
  while( 1 ){
    sqlite3VdbeMemShallowCopy(pOut, pIn1, MEM_Ephem);
    Deephemeralize(pOut);
#ifdef SQLITE_DEBUG
    pOut->pScopyFrom = 0;
#endif
    REGISTER_TRACE(pOp->p2+pOp->p3-u.ae.n, pOut);
    if( (u.ae.n--)==0 ) break;
    pOut++;
    pIn1++;
  }
  break;
}

}

/* Opcode: Permutation * * * P4 *
**
** Set the permutation used by the OP_Compare operator to be the array
** of integers in P4.
**
** The permutation is only valid until the next OP_Compare that has
** the OPFLAG_PERMUTE bit set in P5. Typically the OP_Permutation should 
** occur immediately prior to the OP_Compare.
*/
case OP_Permutation: {
  assert( pOp->p4type==P4_INTARRAY );
  assert( pOp->p4.ai );
  aPermute = pOp->p4.ai;
  break;
}

/* Opcode: Compare P1 P2 P3 P4 P5
**
** Compare two vectors of registers in reg(P1)..reg(P1+P3-1) (call this
** vector "A") and in reg(P2)..reg(P2+P3-1) ("B").  Save the result of
** the comparison for use by the next OP_Jump instruct.
**
** If P5 has the OPFLAG_PERMUTE bit set, then the order of comparison is
** determined by the most recent OP_Permutation operator.  If the
** OPFLAG_PERMUTE bit is clear, then register are compared in sequential
** order.
**
** P4 is a KeyInfo structure that defines collating sequences and sort
** orders for the comparison.  The permutation applies to registers
** only.  The KeyInfo elements are used sequentially.
**
** The comparison is a sort comparison, so NULLs compare equal,
** NULLs are less than numbers, numbers are less than strings,

  int p2;
  const KeyInfo *pKeyInfo;
  int idx;
  CollSeq *pColl;    /* Collating sequence to use on this term */
  int bRev;          /* True for DESCENDING sort order */
#endif /* local variables moved into u.al */

  if( (pOp->p5 & OPFLAG_PERMUTE)==0 ) aPermute = 0;
  u.al.n = pOp->p3;
  u.al.pKeyInfo = pOp->p4.pKeyInfo;
  assert( u.al.n>0 );
  assert( u.al.pKeyInfo!=0 );
  u.al.p1 = pOp->p1;
  u.al.p2 = pOp->p2;
#if SQLITE_DEBUG

** Is equivalent to:
**
**     SELECT random()%5 AS x, count(*) FROM tab GROUP BY random()%5
**
** The result of random()%5 in the GROUP BY clause is probably different
** from the result in the result-set.  We might fix this someday.  Or
** then again, we might not...
**
** If the reference is followed by a COLLATE operator, then make sure
** the COLLATE operator is preserved.  For example:
**
**     SELECT a+b, c+d FROM t1 ORDER BY 1 COLLATE nocase;
**
** Should be transformed into:
**
**     SELECT a+b, c+d FROM t1 ORDER BY (a+b) COLLATE nocase;
**
** The nSubquery parameter specifies how many levels of subquery the
** alias is removed from the original expression.  The usually value is
** zero but it might be more if the alias is contained within a subquery
** of the original expression.  The Expr.op2 field of TK_AGG_FUNCTION
** structures must be increased by the nSubquery amount.
*/

  sqlite3 *db;           /* The database connection */

  assert( iCol>=0 && iCol<pEList->nExpr );
  pOrig = pEList->a[iCol].pExpr;
  assert( pOrig!=0 );
  assert( pOrig->flags & EP_Resolved );
  db = pParse->db;

  pDup = sqlite3ExprDup(db, pOrig, 0);
  if( pDup==0 ) return;
  if( pOrig->op!=TK_COLUMN && zType[0]!='G' ){
    incrAggFunctionDepth(pDup, nSubquery);
    pDup = sqlite3PExpr(pParse, TK_AS, pDup, 0, 0);
    if( pDup==0 ) return;
    if( pEList->a[iCol].iAlias==0 ){
      pEList->a[iCol].iAlias = (u16)(++pParse->nAlias);
    }
    pDup->iTable = pEList->a[iCol].iAlias;













  }
  if( pExpr->op==TK_COLLATE ){

    pDup = sqlite3ExprAddCollateString(pParse, pDup, pExpr->u.zToken);
  }

  /* Before calling sqlite3ExprDelete(), set the EP_Static flag. This 
  ** prevents ExprDelete() from deleting the Expr structure itself,
  ** allowing it to be repopulated by the memcpy() on the following line.
  ** The pExpr->u.zToken might point into memory that will be freed by the
  ** sqlite3DbFree(db, pDup) on the last line of this block, so be sure to
  ** make a copy of the token before doing the sqlite3DbFree().
  */
  ExprSetProperty(pExpr, EP_Static);
  sqlite3ExprDelete(db, pExpr);
  memcpy(pExpr, pDup, sizeof(*pExpr));
  if( !ExprHasProperty(pExpr, EP_IntValue) && pExpr->u.zToken!=0 ){
    assert( (pExpr->flags & (EP_Reduced|EP_TokenOnly))==0 );
    pExpr->u.zToken = sqlite3DbStrDup(db, pExpr->u.zToken);
    pExpr->flags2 |= EP2_MallocedToken;
  }
  sqlite3DbFree(db, pDup);
}


/*
** Return TRUE if the name zCol occurs anywhere in the USING clause.
**

    moreToDo = 0;
    pEList = pSelect->pEList;
    assert( pEList!=0 );
    for(i=0, pItem=pOrderBy->a; i<pOrderBy->nExpr; i++, pItem++){
      int iCol = -1;
      Expr *pE, *pDup;
      if( pItem->done ) continue;
      pE = sqlite3ExprSkipCollate(pItem->pExpr);
      if( sqlite3ExprIsInteger(pE, &iCol) ){
        if( iCol<=0 || iCol>pEList->nExpr ){
          resolveOutOfRangeError(pParse, "ORDER", i+1, pEList->nExpr);
          return 1;
        }
      }else{
        iCol = resolveAsName(pParse, pEList, pE);
        if( iCol==0 ){
          pDup = sqlite3ExprDup(db, pE, 0);
          if( !db->mallocFailed ){
            assert(pDup);
            iCol = resolveOrderByTermToExprList(pParse, pSelect, pDup);
          }
          sqlite3ExprDelete(db, pDup);
        }
      }
      if( iCol>0 ){
        /* Convert the ORDER BY term into an integer column number iCol,
        ** taking care to preserve the COLLATE clause if it exists */

        Expr *pNew = sqlite3Expr(db, TK_INTEGER, 0);
        if( pNew==0 ) return 1;

        pNew->flags |= EP_IntValue;
        pNew->u.iValue = iCol;
        if( pItem->pExpr==pE ){
          pItem->pExpr = pNew;
        }else{
          assert( pItem->pExpr->op==TK_COLLATE );
          assert( pItem->pExpr->pLeft==pE );
          pItem->pExpr->pLeft = pNew;
        }
        sqlite3ExprDelete(db, pE);
        pItem->iOrderByCol = (u16)iCol;
        pItem->done = 1;
      }else{
        moreToDo = 1;
      }
    }
    pSelect = pSelect->pNext;

      /* If an AS-name match is found, mark this ORDER BY column as being
      ** a copy of the iCol-th result-set column.  The subsequent call to
      ** sqlite3ResolveOrderGroupBy() will convert the expression to a
      ** copy of the iCol-th result-set expression. */
      pItem->iOrderByCol = (u16)iCol;
      continue;
    }
    if( sqlite3ExprIsInteger(sqlite3ExprSkipCollate(pE), &iCol) ){
      /* The ORDER BY term is an integer constant.  Again, set the column
      ** number so that sqlite3ResolveOrderGroupBy() will convert the
      ** order-by term to a copy of the result-set expression */
      if( iCol<1 || iCol>0xffff ){
        resolveOutOfRangeError(pParse, zType, i+1, nResult);
        return 1;
      }
      pItem->iOrderByCol = (u16)iCol;
      continue;
    }

**
** CREATE TABLE t1(a);
** SELECT * FROM t1 WHERE a;
** SELECT a AS b FROM t1 WHERE b;
** SELECT * FROM t1 WHERE (select a from t1);
*/
SQLITE_PRIVATE char sqlite3ExprAffinity(Expr *pExpr){
  int op;
  pExpr = sqlite3ExprSkipCollate(pExpr);
  op = pExpr->op;
  if( op==TK_SELECT ){
    assert( pExpr->flags&EP_xIsSelect );
    return sqlite3ExprAffinity(pExpr->x.pSelect->pEList->a[0].pExpr);
  }
#ifndef SQLITE_OMIT_CAST
  if( op==TK_CAST ){
    assert( !ExprHasProperty(pExpr, EP_IntValue) );

    assert( pExpr->pTab && j<pExpr->pTab->nCol );
    return pExpr->pTab->aCol[j].affinity;
  }
  return pExpr->affinity;
}

/*
** Set the collating sequence for expression pExpr to be the collating
** sequence named by pToken.   Return a pointer to a new Expr node that
** implements the COLLATE operator.
**
** If a memory allocation error occurs, that fact is recorded in pParse->db
** and the pExpr parameter is returned unchanged.
*/
SQLITE_PRIVATE Expr *sqlite3ExprAddCollateToken(Parse *pParse, Expr *pExpr, Token *pCollName){
  if( pCollName->n>0 ){
    Expr *pNew = sqlite3ExprAlloc(pParse->db, TK_COLLATE, pCollName, 1);
    if( pNew ){
      pNew->pLeft = pExpr;
      pNew->flags |= EP_Collate;
      pExpr = pNew;
    }
  }
  return pExpr;
}
SQLITE_PRIVATE Expr *sqlite3ExprAddCollateString(Parse *pParse, Expr *pExpr, const char *zC){
  Token s;
  assert( zC!=0 );
  s.z = zC;
  s.n = sqlite3Strlen30(s.z);
  return sqlite3ExprAddCollateToken(pParse, pExpr, &s);
}

/*
** Skip over any TK_COLLATE and/or TK_AS operators at the root of
** an expression.
*/
SQLITE_PRIVATE Expr *sqlite3ExprSkipCollate(Expr *pExpr){
  while( pExpr && (pExpr->op==TK_COLLATE || pExpr->op==TK_AS) ){
    pExpr = pExpr->pLeft;
  }
  return pExpr;
}

/*
** Return the collation sequence for the expression pExpr. If

** there is no defined collating sequence, return NULL.
**
** The collating sequence might be determined by a COLLATE operator
** or by the presence of a column with a defined collating sequence.
** COLLATE operators take first precedence.  Left operands take
** precedence over right operands.
*/
SQLITE_PRIVATE CollSeq *sqlite3ExprCollSeq(Parse *pParse, Expr *pExpr){


  sqlite3 *db = pParse->db;

  CollSeq *pColl = 0;


  Expr *p = pExpr;
  while( p ){
    int op = p->op;
    if( op==TK_CAST || op==TK_UPLUS ){
      p = p->pLeft;
      continue;
    }
    assert( op!=TK_REGISTER || p->op2!=TK_COLLATE );
    if( op==TK_COLLATE ){
      if( db->init.busy ){
        /* Do not report errors when parsing while the schema */
        pColl = sqlite3FindCollSeq(db, ENC(db), p->u.zToken, 0);
      }else{
        pColl = sqlite3GetCollSeq(pParse, ENC(db), 0, p->u.zToken);
      }










      break;

    }
    if( p->pTab!=0
     && (op==TK_AGG_COLUMN || op==TK_COLUMN
          || op==TK_REGISTER || op==TK_TRIGGER)
    ){
      /* op==TK_REGISTER && p->pTab!=0 happens when pExpr was originally
      ** a TK_COLUMN but was previously evaluated and cached in a register */

      int j = p->iColumn;
      if( j>=0 ){

        const char *zColl = p->pTab->aCol[j].zColl;
        pColl = sqlite3FindCollSeq(db, ENC(db), zColl, 0);

      }
      break;
    }
    if( p->flags & EP_Collate ){
      if( ALWAYS(p->pLeft) && (p->pLeft->flags & EP_Collate)!=0 ){
        p = p->pLeft;
      }else{
        p = p->pRight;
      }
    }else{
      break;
    }

  }
  if( sqlite3CheckCollSeq(pParse, pColl) ){ 
    pColl = 0;
  }
  return pColl;
}

SQLITE_PRIVATE CollSeq *sqlite3BinaryCompareCollSeq(
  Parse *pParse, 
  Expr *pLeft, 
  Expr *pRight
){
  CollSeq *pColl;
  assert( pLeft );
  if( pLeft->flags & EP_Collate ){

    pColl = sqlite3ExprCollSeq(pParse, pLeft);
  }else if( pRight && (pRight->flags & EP_Collate)!=0 ){

    pColl = sqlite3ExprCollSeq(pParse, pRight);
  }else{
    pColl = sqlite3ExprCollSeq(pParse, pLeft);
    if( !pColl ){
      pColl = sqlite3ExprCollSeq(pParse, pRight);
    }
  }
  return pColl;

  if( pRoot==0 ){
    assert( db->mallocFailed );
    sqlite3ExprDelete(db, pLeft);
    sqlite3ExprDelete(db, pRight);
  }else{
    if( pRight ){
      pRoot->pRight = pRight;

      pRoot->flags |= EP_Collate & pRight->flags;


    }
    if( pLeft ){
      pRoot->pLeft = pLeft;

      pRoot->flags |= EP_Collate & pLeft->flags;


    }
    exprSetHeight(pRoot);
  }
}

/*
** Allocate a Expr node which joins as many as two subtrees.

  if( 0==(flags&EXPRDUP_REDUCE) ){
    nSize = EXPR_FULLSIZE;
  }else{
    assert( !ExprHasAnyProperty(p, EP_TokenOnly|EP_Reduced) );
    assert( !ExprHasProperty(p, EP_FromJoin) ); 
    assert( (p->flags2 & EP2_MallocedToken)==0 );
    assert( (p->flags2 & EP2_Irreducible)==0 );
    if( p->pLeft || p->pRight || p->x.pList ){
      nSize = EXPR_REDUCEDSIZE | EP_Reduced;
    }else{
      nSize = EXPR_TOKENONLYSIZE | EP_TokenOnly;
    }
  }
  return nSize;
}

      testcase( regFree2==0 );
      codeCompare(pParse, pLeft, pRight, OP_Le, r1, r2, r4, SQLITE_STOREP2);
      sqlite3VdbeAddOp3(v, OP_And, r3, r4, target);
      sqlite3ReleaseTempReg(pParse, r3);
      sqlite3ReleaseTempReg(pParse, r4);
      break;
    }
    case TK_COLLATE: 
    case TK_UPLUS: {
      inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
      break;
    }

    case TK_TRIGGER: {
      /* If the opcode is TK_TRIGGER, then the expression is a reference

    case TK_UMINUS:  zUniOp = "UMINUS"; break;
    case TK_UPLUS:   zUniOp = "UPLUS";  break;
    case TK_BITNOT:  zUniOp = "BITNOT"; break;
    case TK_NOT:     zUniOp = "NOT";    break;
    case TK_ISNULL:  zUniOp = "ISNULL"; break;
    case TK_NOTNULL: zUniOp = "NOTNULL"; break;

    case TK_COLLATE: {
      sqlite3ExplainExpr(pOut, pExpr->pLeft);
      sqlite3ExplainPrintf(pOut,".COLLATE(%s)",pExpr->u.zToken);
      break;
    }

    case TK_AGG_FUNCTION:
    case TK_CONST_FUNC:
    case TK_FUNCTION: {
      ExprList *pFarg;       /* List of function arguments */
      if( ExprHasAnyProperty(pExpr, EP_TokenOnly) ){
        pFarg = 0;

static int evalConstExpr(Walker *pWalker, Expr *pExpr){
  Parse *pParse = pWalker->pParse;
  switch( pExpr->op ){
    case TK_IN:
    case TK_REGISTER: {
      return WRC_Prune;
    }
    case TK_COLLATE: {
      return WRC_Continue;
    }
    case TK_FUNCTION:
    case TK_AGG_FUNCTION:
    case TK_CONST_FUNC: {
      /* The arguments to a function have a fixed destination.
      ** Mark them this way to avoid generated unneeded OP_SCopy
      ** instructions. 
      */

        }
      }
      break;
    }
  }
  if( isAppropriateForFactoring(pExpr) ){
    int r1 = ++pParse->nMem;

    int r2 = sqlite3ExprCodeTarget(pParse, pExpr, r1);
    /* If r2!=r1, it means that register r1 is never used.  That is harmless
    ** but suboptimal, so we want to know about the situation to fix it.
    ** Hence the following assert: */
    assert( r2==r1 );
    pExpr->op2 = pExpr->op;
    pExpr->op = TK_REGISTER;
    pExpr->iTable = r2;
    return WRC_Prune;
  }
  return WRC_Continue;
}

  }
  assert( !ExprHasAnyProperty(pA, EP_TokenOnly|EP_Reduced) );
  assert( !ExprHasAnyProperty(pB, EP_TokenOnly|EP_Reduced) );
  if( ExprHasProperty(pA, EP_xIsSelect) || ExprHasProperty(pB, EP_xIsSelect) ){
    return 2;
  }
  if( (pA->flags & EP_Distinct)!=(pB->flags & EP_Distinct) ) return 2;
  if( pA->op!=pB->op ){
    if( pA->op==TK_COLLATE && sqlite3ExprCompare(pA->pLeft, pB)<2 ){
      return 1;
    }
    if( pB->op==TK_COLLATE && sqlite3ExprCompare(pA, pB->pLeft)<2 ){
      return 1;
    }
    return 2;
  }
  if( sqlite3ExprCompare(pA->pLeft, pB->pLeft) ) return 2;
  if( sqlite3ExprCompare(pA->pRight, pB->pRight) ) return 2;
  if( sqlite3ExprListCompare(pA->x.pList, pB->x.pList) ) return 2;
  if( pA->iTable!=pB->iTable || pA->iColumn!=pB->iColumn ) return 2;
  if( ExprHasProperty(pA, EP_IntValue) ){
    if( !ExprHasProperty(pB, EP_IntValue) || pA->u.iValue!=pB->u.iValue ){
      return 2;
    }
  }else if( pA->op!=TK_COLUMN && ALWAYS(pA->op!=TK_AGG_COLUMN) && pA->u.zToken){
    if( ExprHasProperty(pB, EP_IntValue) || NEVER(pB->u.zToken==0) ) return 2;
    if( strcmp(pA->u.zToken,pB->u.zToken)!=0 ){
      return pA->op==TK_COLLATE ? 1 : 2;
    }
  }


  return 0;
}

/*
** Compare two ExprList objects.  Return 0 if they are identical and 
** non-zero if they differ in any way.
**

** Note that if an error occurred, it might be the case that
** no VDBE code was generated.
*/
SQLITE_PRIVATE void sqlite3FinishCoding(Parse *pParse){
  sqlite3 *db;
  Vdbe *v;

  assert( pParse->pToplevel==0 );
  db = pParse->db;
  if( db->mallocFailed ) return;
  if( pParse->nested ) return;
  if( pParse->nErr ) return;

  /* Begin by generating some termination code at the end of the
  ** vdbe program

  /* Figure out how many bytes of space are required to store explicitly
  ** specified collation sequence names.
  */
  for(i=0; i<pList->nExpr; i++){
    Expr *pExpr = pList->a[i].pExpr;
    if( pExpr ){
      CollSeq *pColl = sqlite3ExprCollSeq(pParse, pExpr);


      if( pColl ){
        nExtra += (1 + sqlite3Strlen30(pColl->zName));
      }
    }
  }

  /* 
  ** Allocate the index structure. 

  ** same column more than once cannot be an error because that would 
  ** break backwards compatibility - it needs to be a warning.
  */
  for(i=0, pListItem=pList->a; i<pList->nExpr; i++, pListItem++){
    const char *zColName = pListItem->zName;
    Column *pTabCol;
    int requestedSortOrder;
    CollSeq *pColl;                /* Collating sequence */
    char *zColl;                   /* Collation sequence name */

    for(j=0, pTabCol=pTab->aCol; j<pTab->nCol; j++, pTabCol++){
      if( sqlite3StrICmp(zColName, pTabCol->zName)==0 ) break;
    }
    if( j>=pTab->nCol ){
      sqlite3ErrorMsg(pParse, "table %s has no column named %s",
        pTab->zName, zColName);
      pParse->checkSchema = 1;
      goto exit_create_index;
    }
    pIndex->aiColumn[i] = j;





    if( pListItem->pExpr
     && (pColl = sqlite3ExprCollSeq(pParse, pListItem->pExpr))!=0
    ){
      int nColl;
      zColl = pColl->zName;
      nColl = sqlite3Strlen30(zColl) + 1;
      assert( nExtra>=nColl );
      memcpy(zExtra, zColl, nColl);
      zColl = zExtra;
      zExtra += nColl;
      nExtra -= nColl;
    }else{

** If iDb<0 then code the OP_Goto only - don't set flag to verify the
** schema on any databases.  This can be used to position the OP_Goto
** early in the code, before we know if any database tables will be used.
*/
SQLITE_PRIVATE void sqlite3CodeVerifySchema(Parse *pParse, int iDb){
  Parse *pToplevel = sqlite3ParseToplevel(pParse);

#ifndef SQLITE_OMIT_TRIGGER
  if( pToplevel!=pParse ){
    /* This branch is taken if a trigger is currently being coded. In this
    ** case, set cookieGoto to a non-zero value to show that this function
    ** has been called. This is used by the sqlite3ExprCodeConstants()
    ** function. */
    pParse->cookieGoto = -1;
  }
#endif
  if( pToplevel->cookieGoto==0 ){
    Vdbe *v = sqlite3GetVdbe(pToplevel);
    if( v==0 ) return;  /* This only happens if there was a prior error */
    pToplevel->cookieGoto = sqlite3VdbeAddOp2(v, OP_Goto, 0, 0)+1;
  }
  if( iDb>=0 ){
    sqlite3 *db = pToplevel->db;

    pLeft = sqlite3Expr(db, TK_REGISTER, 0);
    if( pLeft ){
      /* Set the collation sequence and affinity of the LHS of each TK_EQ
      ** expression to the parent key column defaults.  */
      if( pIdx ){
        Column *pCol;
        const char *zColl;
        iCol = pIdx->aiColumn[i];
        pCol = &pTab->aCol[iCol];
        if( pTab->iPKey==iCol ) iCol = -1;
        pLeft->iTable = regData+iCol+1;
        pLeft->affinity = pCol->affinity;
        zColl = pCol->zColl;
        if( zColl==0 ) zColl = db->pDfltColl->zName;
        pLeft = sqlite3ExprAddCollateString(pParse, pLeft, zColl);
      }else{
        pLeft->iTable = regData;
        pLeft->affinity = SQLITE_AFF_INTEGER;
      }
    }
    iCol = aiCol ? aiCol[i] : pFKey->aCol[0].iFrom;
    assert( iCol>=0 );

#ifndef SQLITE_OMIT_CHECK
  if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
    ExprList *pCheck = pTab->pCheck;
    pParse->ckBase = regData;
    onError = overrideError!=OE_Default ? overrideError : OE_Abort;
    for(i=0; i<pCheck->nExpr; i++){
      int allOk = sqlite3VdbeMakeLabel(v);



      sqlite3ExprIfTrue(pParse, pCheck->a[i].pExpr, allOk, SQLITE_JUMPIFNULL);
      if( onError==OE_Ignore ){
        sqlite3VdbeAddOp2(v, OP_Goto, 0, ignoreDest);
      }else{
        char *zConsName = pCheck->a[i].zName;
        if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */
        if( zConsName ){
          zConsName = sqlite3MPrintf(db, "constraint %s failed", zConsName);
        }else{
          zConsName = 0;
        }
        sqlite3HaltConstraint(pParse, onError, zConsName, P4_DYNAMIC);
      }
      sqlite3VdbeResolveLabel(v, allOk);


    }
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* If we have an INTEGER PRIMARY KEY, make sure the primary key
  ** of the new record does not previously exist.  Except, if this
  ** is an UPDATE and the primary key is not changing, that is OK.

  }
  *pnCol = nCol;
  *paCol = aCol;

  for(i=0, pCol=aCol; i<nCol; i++, pCol++){
    /* Get an appropriate name for the column
    */
    p = sqlite3ExprSkipCollate(pEList->a[i].pExpr);
    assert( p->pRight==0 || ExprHasProperty(p->pRight, EP_IntValue)
               || p->pRight->u.zToken==0 || p->pRight->u.zToken[0]!=0 );
    if( (zName = pEList->a[i].zName)!=0 ){
      /* If the column contains an "AS <name>" phrase, use <name> as the name */
      zName = sqlite3DbStrDup(db, zName);
    }else{
      Expr *pColExpr = p;  /* The expression that is the result column name */

    if( pKeyMerge ){
      pKeyMerge->aSortOrder = (u8*)&pKeyMerge->aColl[nOrderBy];
      pKeyMerge->nField = (u16)nOrderBy;
      pKeyMerge->enc = ENC(db);
      for(i=0; i<nOrderBy; i++){
        CollSeq *pColl;
        Expr *pTerm = pOrderBy->a[i].pExpr;
        if( pTerm->flags & EP_Collate ){
          pColl = sqlite3ExprCollSeq(pParse, pTerm);
        }else{
          pColl = multiSelectCollSeq(pParse, p, aPermute[i]);
          if( pColl==0 ) pColl = db->pDfltColl;
          pOrderBy->a[i].pExpr =
             sqlite3ExprAddCollateString(pParse, pTerm, pColl->zName);
        }
        pKeyMerge->aColl[i] = pColl;
        pKeyMerge->aSortOrder[i] = pOrderBy->a[i].sortOrder;
      }
    }
  }else{
    pKeyMerge = 0;

  /* Implement the main merge loop
  */
  sqlite3VdbeResolveLabel(v, labelCmpr);
  sqlite3VdbeAddOp4(v, OP_Permutation, 0, 0, 0, (char*)aPermute, P4_INTARRAY);
  sqlite3VdbeAddOp4(v, OP_Compare, destA.iSdst, destB.iSdst, nOrderBy,
                         (char*)pKeyMerge, P4_KEYINFO_HANDOFF);
  sqlite3VdbeChangeP5(v, OPFLAG_PERMUTE);
  sqlite3VdbeAddOp3(v, OP_Jump, addrAltB, addrAeqB, addrAgtB);

  /* Release temporary registers
  */
  if( regPrev ){
    sqlite3ReleaseTempRange(pParse, regPrev, nOrderBy+1);
  }

    if( pExpr->iColumn<0 ){
      pExpr->op = TK_NULL;
    }else{
      Expr *pNew;
      assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
      assert( pExpr->pLeft==0 && pExpr->pRight==0 );
      pNew = sqlite3ExprDup(db, pEList->a[pExpr->iColumn].pExpr, 0);



      sqlite3ExprDelete(db, pExpr);
      pExpr = pNew;
    }
  }else{
    pExpr->pLeft = substExpr(db, pExpr->pLeft, iTable, pEList);
    pExpr->pRight = substExpr(db, pExpr->pRight, iTable, pEList);
    if( ExprHasProperty(pExpr, EP_xIsSelect) ){

      /* Implement a co-routine that will return a single row of the result
      ** set on each invocation.
      */
      int addrTop;
      int addrEof;
      pItem->regReturn = ++pParse->nMem;
      addrEof = ++pParse->nMem;
      /* Before coding the OP_Goto to jump to the start of the main routine,
      ** ensure that the jump to the verify-schema routine has already
      ** been coded. Otherwise, the verify-schema would likely be coded as 
      ** part of the co-routine. If the main routine then accessed the 
      ** database before invoking the co-routine for the first time (for 
      ** example to initialize a LIMIT register from a sub-select), it would 
      ** be doing so without having verified the schema version and obtained 
      ** the required db locks. See ticket d6b36be38.  */
      sqlite3CodeVerifySchema(pParse, -1);
      sqlite3VdbeAddOp0(v, OP_Goto);
      addrTop = sqlite3VdbeAddOp1(v, OP_OpenPseudo, pItem->iCursor);
      sqlite3VdbeChangeP5(v, 1);
      VdbeComment((v, "coroutine for %s", pItem->pTab->zName));
      pItem->addrFillSub = addrTop;
      sqlite3VdbeAddOp2(v, OP_Integer, 0, addrEof);
      sqlite3VdbeChangeP5(v, 1);

    **     INSERT OR REPLACE INTO t2 VALUES(new.a, new.b);
    **   END;
    **
    **   INSERT INTO t1 ... ;            -- insert into t2 uses REPLACE policy
    **   INSERT OR IGNORE INTO t1 ... ;  -- insert into t2 uses IGNORE policy
    */
    pParse->eOrconf = (orconf==OE_Default)?pStep->orconf:(u8)orconf;

    /* Clear the cookieGoto flag. When coding triggers, the cookieGoto 
    ** variable is used as a flag to indicate to sqlite3ExprCodeConstants()
    ** that it is not safe to refactor constants (this happens after the
    ** start of the first loop in the SQL statement is coded - at that 
    ** point code may be conditionally executed, so it is no longer safe to 
    ** initialize constant register values).  */
    assert( pParse->cookieGoto==0 || pParse->cookieGoto==-1 );
    pParse->cookieGoto = 0;

    switch( pStep->op ){
      case TK_UPDATE: {
        sqlite3Update(pParse, 
          targetSrcList(pParse, pStep),
          sqlite3ExprListDup(db, pStep->pExprList, 0), 
          sqlite3ExprDup(db, pStep->pWhere, 0), 

*/
#define SWAP(TYPE,A,B) {TYPE t=A; A=B; B=t;}

/*
** Commute a comparison operator.  Expressions of the form "X op Y"
** are converted into "Y op X".
**
** If left/right precendence rules come into play when determining the
** collating
** side of the comparison, it remains associated with the same side after
** the commutation. So "Y collate NOCASE op X" becomes 
** "X op Y". This is because any collation sequence on
** the left hand side of a comparison overrides any collation sequence 
** attached to the right. For the same reason the EP_Collate flag
** is not commuted.
*/
static void exprCommute(Parse *pParse, Expr *pExpr){
  u16 expRight = (pExpr->pRight->flags & EP_Collate);
  u16 expLeft = (pExpr->pLeft->flags & EP_Collate);
  assert( allowedOp(pExpr->op) && pExpr->op!=TK_IN );
  if( expRight==expLeft ){
    /* Either X and Y both have COLLATE operator or neither do */
    if( expRight ){
      /* Both X and Y have COLLATE operators.  Make sure X is always
      ** used by clearing the EP_Collate flag from Y. */
      pExpr->pRight->flags &= ~EP_Collate;
    }else if( sqlite3ExprCollSeq(pParse, pExpr->pLeft)!=0 ){

      /* Neither X nor Y have COLLATE operators, but X has a non-default
      ** collating sequence.  So add the EP_Collate marker on X to cause
      ** it to be searched first. */
      pExpr->pLeft->flags |= EP_Collate;
    }
  }
  SWAP(Expr*,pExpr->pRight,pExpr->pLeft);
  if( pExpr->op>=TK_GT ){
    assert( TK_LT==TK_GT+2 );
    assert( TK_GE==TK_LE+2 );
    assert( TK_GT>TK_EQ );
    assert( TK_GT<TK_LE );
    assert( pExpr->op>=TK_GT && pExpr->op<=TK_GE );

  
          /* 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 = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
          if( pColl==0 ) pColl = pParse->db->pDfltColl;
  
          for(j=0; pIdx->aiColumn[j]!=iColumn; j++){
            if( NEVER(j>=pIdx->nColumn) ) return 0;
          }
          if( sqlite3StrICmp(pColl->zName, pIdx->azColl[j]) ) continue;
        }
        return pTerm;
      }
    }
  }
  return 0;
}

  sqlite3 *db = pParse->db;        /* Database connection */

  if( db->mallocFailed ){
    return;
  }
  pTerm = &pWC->a[idxTerm];
  pMaskSet = pWC->pMaskSet;
  pExpr = sqlite3ExprSkipCollate(pTerm->pExpr);
  prereqLeft = exprTableUsage(pMaskSet, pExpr->pLeft);
  op = pExpr->op;
  if( op==TK_IN ){
    assert( pExpr->pRight==0 );
    if( ExprHasProperty(pExpr, EP_xIsSelect) ){
      pTerm->prereqRight = exprSelectTableUsage(pMaskSet, pExpr->x.pSelect);
    }else{

                       ** on left table of a LEFT JOIN.  Ticket #3015 */
  }
  pTerm->prereqAll = prereqAll;
  pTerm->leftCursor = -1;
  pTerm->iParent = -1;
  pTerm->eOperator = 0;
  if( allowedOp(op) && (pTerm->prereqRight & prereqLeft)==0 ){
    Expr *pLeft = sqlite3ExprSkipCollate(pExpr->pLeft);
    Expr *pRight = sqlite3ExprSkipCollate(pExpr->pRight);
    if( pLeft->op==TK_COLUMN ){
      pTerm->leftCursor = pLeft->iTable;
      pTerm->u.leftColumn = pLeft->iColumn;
      pTerm->eOperator = operatorMask(op);
    }
    if( pRight && pRight->op==TK_COLUMN ){
      WhereTerm *pNew;

        pTerm->nChild = 1;
        pTerm->wtFlags |= TERM_COPIED;
      }else{
        pDup = pExpr;
        pNew = pTerm;
      }
      exprCommute(pParse, pDup);
      pLeft = sqlite3ExprSkipCollate(pDup->pLeft);
      pNew->leftCursor = pLeft->iTable;
      pNew->u.leftColumn = pLeft->iColumn;
      testcase( (prereqLeft | extraRight) != prereqLeft );
      pNew->prereqRight = prereqLeft | extraRight;
      pNew->prereqAll = prereqAll;
      pNew->eOperator = operatorMask(pDup->op);
    }

  ){
    Expr *pLeft;       /* LHS of LIKE/GLOB operator */
    Expr *pStr2;       /* Copy of pStr1 - RHS of LIKE/GLOB operator */
    Expr *pNewExpr1;
    Expr *pNewExpr2;
    int idxNew1;
    int idxNew2;
    Token sCollSeqName;  /* Name of collating sequence */

    pLeft = pExpr->x.pList->a[1].pExpr;
    pStr2 = sqlite3ExprDup(db, pStr1, 0);
    if( !db->mallocFailed ){
      u8 c, *pC;       /* Last character before the first wildcard */
      pC = (u8*)&pStr2->u.zToken[sqlite3Strlen30(pStr2->u.zToken)-1];
      c = *pC;

        if( c=='A'-1 ) isComplete = 0;   /* EV: R-64339-08207 */


        c = sqlite3UpperToLower[c];
      }
      *pC = c + 1;
    }
    sCollSeqName.z = noCase ? "NOCASE" : "BINARY";
    sCollSeqName.n = 6;
    pNewExpr1 = sqlite3ExprDup(db, pLeft, 0);
    pNewExpr1 = sqlite3PExpr(pParse, TK_GE, 
           sqlite3ExprAddCollateToken(pParse,pNewExpr1,&sCollSeqName),
           pStr1, 0);
    idxNew1 = whereClauseInsert(pWC, pNewExpr1, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew1==0 );
    exprAnalyze(pSrc, pWC, idxNew1);
    pNewExpr2 = sqlite3ExprDup(db, pLeft, 0);
    pNewExpr2 = sqlite3PExpr(pParse, TK_LT,
           sqlite3ExprAddCollateToken(pParse,pNewExpr2,&sCollSeqName),
           pStr2, 0);
    idxNew2 = whereClauseInsert(pWC, pNewExpr2, TERM_VIRTUAL|TERM_DYNAMIC);
    testcase( idxNew2==0 );
    exprAnalyze(pSrc, pWC, idxNew2);
    pTerm = &pWC->a[idxTerm];
    if( isComplete ){
      pWC->a[idxNew1].iParent = idxTerm;
      pWC->a[idxNew2].iParent = idxTerm;

  Index *pIdx,                    /* Index to match column of */
  int iCol                        /* Column of index to match */
){
  int i;
  const char *zColl = pIdx->azColl[iCol];

  for(i=0; i<pList->nExpr; i++){
    Expr *p = sqlite3ExprSkipCollate(pList->a[i].pExpr);
    if( p->op==TK_COLUMN
     && p->iColumn==pIdx->aiColumn[iCol]
     && p->iTable==iBase
    ){
      CollSeq *pColl = sqlite3ExprCollSeq(pParse, pList->a[i].pExpr);
      if( ALWAYS(pColl) && 0==sqlite3StrICmp(pColl->zName, zColl) ){
        return i;
      }
    }
  }

  return -1;

  ** can be ignored. If it does not, and the column does not belong to the
  ** same table as index pIdx, return early. Finally, if there is no
  ** matching "col=X" expression and the column is on the same table as pIdx,
  ** set the corresponding bit in variable mask.
  */
  for(i=0; i<pDistinct->nExpr; i++){
    WhereTerm *pTerm;
    Expr *p = sqlite3ExprSkipCollate(pDistinct->a[i].pExpr);
    if( p->op!=TK_COLUMN ) return 0;
    pTerm = findTerm(pWC, p->iTable, p->iColumn, ~(Bitmask)0, WO_EQ, 0);
    if( pTerm ){
      Expr *pX = pTerm->pExpr;
      CollSeq *p1 = sqlite3BinaryCompareCollSeq(pParse, pX->pLeft, pX->pRight);
      CollSeq *p2 = sqlite3ExprCollSeq(pParse, p);
      if( p1==p2 ) continue;

  pTab = pTabList->a[0].pTab;

  /* If any of the expressions is an IPK column on table iBase, then return 
  ** true. Note: The (p->iTable==iBase) part of this test may be false if the
  ** current SELECT is a correlated sub-query.
  */
  for(i=0; i<pDistinct->nExpr; i++){
    Expr *p = sqlite3ExprSkipCollate(pDistinct->a[i].pExpr);
    if( p->op==TK_COLUMN && p->iTable==iBase && p->iColumn<0 ) return 1;
  }

  /* Loop through all indices on the table, checking each to see if it makes
  ** the DISTINCT qualifier redundant. It does so if:
  **
  **   1. The index is itself UNIQUE, and

    int isMatch;            /* ORDER BY term matches the index term */
    const char *zColl;      /* Name of collating sequence for i-th index term */
    WhereTerm *pConstraint; /* A constraint in the WHERE clause */

    /* If the next term of the ORDER BY clause refers to anything other than
    ** a column in the "base" table, then this index will not be of any
    ** further use in handling the ORDER BY. */
    pOBExpr = sqlite3ExprSkipCollate(pOBItem->pExpr);
    if( pOBExpr->op!=TK_COLUMN || pOBExpr->iTable!=base ){
      break;
    }

    /* Find column number and collating sequence for the next entry
    ** in the index */
    if( pIdx->zName && i<pIdx->nColumn ){

    }

    /* Check to see if the column number and collating sequence of the
    ** index match the column number and collating sequence of the ORDER BY
    ** clause entry.  Set isMatch to 1 if they both match. */
    if( pOBExpr->iColumn==iColumn ){
      if( zColl ){
        pColl = sqlite3ExprCollSeq(pParse, pOBItem->pExpr);
        if( !pColl ) pColl = db->pDfltColl;
        isMatch = sqlite3StrICmp(pColl->zName, zColl)==0;
      }else{
        isMatch = 1;
      }
    }else{
      isMatch = 0;

  Index *pIdx;                /* Copy of pProbe, or zero for IPK index */
  int eqTermMask;             /* Current mask of valid equality operators */
  int idxEqTermMask;          /* Index mask of valid equality operators */
  Index sPk;                  /* A fake index object for the primary key */
  tRowcnt aiRowEstPk[2];      /* The aiRowEst[] value for the sPk index */
  int aiColumnPk = -1;        /* The aColumn[] value for the sPk index */
  int wsFlagMask;             /* Allowed flags in p->cost.plan.wsFlag */
  int nPriorSat;              /* ORDER BY terms satisfied by outer loops */
  int nOrderBy;               /* Number of ORDER BY terms */
  char bSortInit;             /* Initializer for bSort in inner loop */
  char bDistInit;             /* Initializer for bDist in inner loop */


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

  /* If the pSrc table is the right table of a LEFT JOIN then we may not
  ** use an index to satisfy IS NULL constraints on that table.  This is

    pProbe = &sPk;
    wsFlagMask = ~(
        WHERE_COLUMN_IN|WHERE_COLUMN_EQ|WHERE_COLUMN_NULL|WHERE_COLUMN_RANGE
    );
    eqTermMask = WO_EQ|WO_IN;
    pIdx = 0;
  }

  nOrderBy = p->pOrderBy ? p->pOrderBy->nExpr : 0;
  if( p->i ){
    nPriorSat = p->aLevel[p->i-1].plan.nOBSat;
    bSortInit = nPriorSat<nOrderBy;
    bDistInit = 0;
  }else{
    nPriorSat = 0;
    bSortInit = nOrderBy>0;
    bDistInit = p->pDistinct!=0;
  }

  /* Loop over all indices looking for the best one to use
  */
  for(; pProbe; pIdx=pProbe=pProbe->pNext){
    const tRowcnt * const aiRowEst = pProbe->aiRowEst;
    WhereCost pc;               /* Cost of using pProbe */
    double log10N = (double)1;  /* base-10 logarithm of nRow (inexact) */

    **             SELECT a, b    FROM tbl WHERE a = 1;
    **             SELECT a, b, c FROM tbl WHERE a = 1;
    */
    int bInEst = 0;               /* True if "x IN (SELECT...)" seen */
    int nInMul = 1;               /* Number of distinct equalities to lookup */
    double rangeDiv = (double)1;  /* Estimated reduction in search space */
    int nBound = 0;               /* Number of range constraints seen */
    char bSort = bSortInit;       /* True if external sort required */
    char bDist = bDistInit;       /* True if index cannot help with DISTINCT */
    char bLookup = 0;             /* True if not a covering index */


    WhereTerm *pTerm;             /* A single term of the WHERE clause */
#ifdef SQLITE_ENABLE_STAT3
    WhereTerm *pFirstTerm = 0;    /* First term matching the index */
#endif

    WHERETRACE((
      "   %s(%s):\n",
      pSrc->pTab->zName, (pIdx ? pIdx->zName : "ipk")
    ));
    memset(&pc, 0, sizeof(pc));






    pc.plan.nOBSat = nPriorSat;




    /* Determine the values of pc.plan.nEq and nInMul */
    for(pc.plan.nEq=0; pc.plan.nEq<pProbe->nColumn; pc.plan.nEq++){
      int j = pProbe->aiColumn[pc.plan.nEq];
      pTerm = findTerm(pWC, iCur, j, p->notReady, eqTermMask, pIdx);
      if( pTerm==0 ) break;
      pc.plan.wsFlags |= (WHERE_COLUMN_EQ|WHERE_ROWID_EQ);

  spanExpr(&yygotominor.yy342, pParse, TK_VARIABLE, &yymsp[0].minor.yy0);
  sqlite3ExprAssignVarNumber(pParse, yygotominor.yy342.pExpr);
  spanSet(&yygotominor.yy342, &yymsp[0].minor.yy0, &yymsp[0].minor.yy0);
}
        break;
      case 194: /* expr ::= expr COLLATE ids */
{
  yygotominor.yy342.pExpr = sqlite3ExprAddCollateToken(pParse, yymsp[-2].minor.yy342.pExpr, &yymsp[0].minor.yy0);
  yygotominor.yy342.zStart = yymsp[-2].minor.yy342.zStart;
  yygotominor.yy342.zEnd = &yymsp[0].minor.yy0.z[yymsp[0].minor.yy0.n];
}
        break;
      case 195: /* expr ::= CAST LP expr AS typetoken RP */
{
  yygotominor.yy342.pExpr = sqlite3PExpr(pParse, TK_CAST, yymsp[-3].minor.yy342.pExpr, 0, &yymsp[-1].minor.yy0);

{yygotominor.yy392 = OE_Abort;}
        break;
      case 244: /* uniqueflag ::= */
{yygotominor.yy392 = OE_None;}
        break;
      case 247: /* idxlist ::= idxlist COMMA nm collate sortorder */
{

  Expr *p = sqlite3ExprAddCollateToken(pParse, 0, &yymsp[-1].minor.yy0);



  yygotominor.yy442 = sqlite3ExprListAppend(pParse,yymsp[-4].minor.yy442, p);
  sqlite3ExprListSetName(pParse,yygotominor.yy442,&yymsp[-2].minor.yy0,1);
  sqlite3ExprListCheckLength(pParse, yygotominor.yy442, "index");
  if( yygotominor.yy442 ) yygotominor.yy442->a[yygotominor.yy442->nExpr-1].sortOrder = (u8)yymsp[0].minor.yy392;
}
        break;
      case 248: /* idxlist ::= nm collate sortorder */
{

  Expr *p = sqlite3ExprAddCollateToken(pParse, 0, &yymsp[-1].minor.yy0);



  yygotominor.yy442 = sqlite3ExprListAppend(pParse,0, p);
  sqlite3ExprListSetName(pParse, yygotominor.yy442, &yymsp[-2].minor.yy0, 1);
  sqlite3ExprListCheckLength(pParse, yygotominor.yy442, "index");
  if( yygotominor.yy442 ) yygotominor.yy442->a[yygotominor.yy442->nExpr-1].sortOrder = (u8)yymsp[0].minor.yy392;
}
        break;
      case 249: /* collate ::= */