SQLite

*/
typedef struct SubstContext {
  Parse *pParse;            /* The parsing context */
  int iTable;               /* Replace references to this table */
  int iNewTable;            /* New table number */
  int isOuterJoin;          /* Add TK_IF_NULL_ROW opcodes on each replacement */
  ExprList *pEList;         /* Replacement expressions */
  ExprList *pCList;         /* Collation sequences for replacement expr */
} SubstContext;

/* Forward Declarations */
static void substExprList(SubstContext*, ExprList*);
static void substSelect(SubstContext*, Select*, int);

/*

#ifdef SQLITE_ALLOW_ROWID_IN_VIEW
    if( pExpr->iColumn<0 ){
      pExpr->op = TK_NULL;
    }else
#endif
    {
      Expr *pNew;
      int iColumn = pExpr->iColumn;
      Expr *pCopy = pSubst->pEList->a[iColumn].pExpr;
      Expr ifNullRow;
      assert( pSubst->pEList!=0 && iColumn<pSubst->pEList->nExpr );
      assert( pExpr->pRight==0 );
      if( sqlite3ExprIsVector(pCopy) ){
        sqlite3VectorErrorMsg(pSubst->pParse, pCopy);
      }else{
        sqlite3 *db = pSubst->pParse->db;
        if( pSubst->isOuterJoin && pCopy->op!=TK_COLUMN ){
          memset(&ifNullRow, 0, sizeof(ifNullRow));

          pExpr->u.iValue = sqlite3ExprTruthValue(pExpr);
          pExpr->op = TK_INTEGER;
          ExprSetProperty(pExpr, EP_IntValue);
        }

        /* Ensure that the expression now has an implicit collation sequence,
        ** just as it did when it was a column of a view or sub-query. */
        {
          CollSeq *pNat = sqlite3ExprCollSeq(pSubst->pParse, pExpr);
          CollSeq *pColl = sqlite3ExprCollSeq(pSubst->pParse,
                pSubst->pCList->a[iColumn].pExpr
          );
          if( pNat!=pColl || (pExpr->op!=TK_COLUMN && pExpr->op!=TK_COLLATE) ){
            pExpr = sqlite3ExprAddCollateString(pSubst->pParse, pExpr,
                (pColl ? pColl->zName : "BINARY")
            );
          }
        }
        ExprClearProperty(pExpr, EP_Collate);
      }
    }
  }else{
    if( pExpr->op==TK_IF_NULL_ROW && pExpr->iTable==pSubst->iTable ){
      pExpr->iTable = pSubst->iNewTable;

  memset(&w, 0, sizeof(w));
  w.u.aiCol = aCsrMap;
  w.xExprCallback = renumberCursorsCb;
  w.xSelectCallback = sqlite3SelectWalkNoop;
  sqlite3WalkSelect(&w, p);
}
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */

/*
** If pSel is not part of a compound SELECT, return a pointer to its
** expression list. Otherwise, return a pointer to the expression list
** of the leftmost SELECT in the compound.
*/
static ExprList *findLeftmostExprlist(Select *pSel){
  while( pSel->pPrior ){
    pSel = pSel->pPrior;
  }
  return pSel->pEList;
}

#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
/*
** This routine attempts to flatten subqueries as a performance optimization.
** This routine returns 1 if it makes changes and 0 if no flattening occurs.
**
** To understand the concept of flattening, consider the following

    if( db->mallocFailed==0 ){
      SubstContext x;
      x.pParse = pParse;
      x.iTable = iParent;
      x.iNewTable = iNewParent;
      x.isOuterJoin = isOuterJoin;
      x.pEList = pSub->pEList;
      x.pCList = findLeftmostExprlist(pSub);
      substSelect(&x, pParent, 0);
    }
  
    /* The flattened query is a compound if either the inner or the
    ** outer query is a compound. */
    pParent->selFlags |= pSub->selFlags & SF_Compound;
    assert( (pSub->selFlags & SF_Distinct)==0 ); /* restriction (17b) */

      pNew = sqlite3ExprDup(pParse->db, pWhere, 0);
      unsetJoinExpr(pNew, -1, 1);
      x.pParse = pParse;
      x.iTable = pSrc->iCursor;
      x.iNewTable = pSrc->iCursor;
      x.isOuterJoin = 0;
      x.pEList = pSubq->pEList;
      x.pCList = findLeftmostExprlist(pSubq);
      pNew = substExpr(&x, pNew);
#ifndef SQLITE_OMIT_WINDOWFUNC
      if( pSubq->pWin && 0==pushDownWindowCheck(pParse, pSubq, pNew) ){
        /* Restriction 6c has prevented push-down in this case */
        sqlite3ExprDelete(pParse->db, pNew);
        nChng--;
        break;

# GROUP BY clauses that use user-defined collation sequences.
#
# $Id: collate5.test,v 1.7 2008/09/16 11:58:20 drh Exp $

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

set testprefix collate5


#
# Tests are organised as follows:
# collate5-1.* - DISTINCT
# collate5-2.* - Compound SELECT
# collate5-3.* - ORDER BY on compound SELECT
# collate5-4.* - GROUP BY
# collate5-5.* - Collation sequence cases

# Create the collation sequence 'TEXT', purely for asthetic reasons. The
# test cases in this script could just as easily use BINARY.
db collate TEXT [list string compare]

# Mimic the SQLite 2 collation type NUMERIC.
db collate numeric numeric_collate

  }
} {/[aA] 1(.0)? 2 [bB] 2 1 [bB] 3 1/}
do_test collate5-4.3 {
  execsql {
    DROP TABLE collate5t1;
  }
} {}

#-------------------------------------------------------------------------
reset_db

do_execsql_test 5.0 {
  CREATE TABLE t1(a, b COLLATE nocase);
  CREATE TABLE t2(c, d);
  INSERT INTO t2 VALUES(1, 'bbb');
}
do_execsql_test 5.1 {
  SELECT * FROM (
      SELECT a, b FROM t1 UNION ALL SELECT c, d FROM t2
  ) WHERE b='BbB';
} {1 bbb}

reset_db
do_execsql_test 5.2 {
  CREATE TABLE t1(a,b,c COLLATE NOCASE);
  INSERT INTO t1 VALUES(NULL,'C','c');
  CREATE VIEW v2 AS
    SELECT a,b,c FROM t1 INTERSECT SELECT a,b,b FROM t1
    WHERE 'eT"3qRkL+oJMJjQ9z0'>=b
    ORDER BY a,b,c;
}

do_execsql_test 5.3 {
  SELECT * FROM v2;
} { {} C c }

do_execsql_test 5.4 {
  SELECT * FROM v2 WHERE c='c';
} { {} C c }


finish_test