SQLite

/*
** Return the bitwise-OR of all Expr.flags fields in the given
** ExprList.
*/
u32 sqlite3ExprListFlags(const ExprList *pList){
  int i;
  u32 m = 0;
  assert( pList!=0 );
  for(i=0; i<pList->nExpr; i++){
     Expr *pExpr = pList->a[i].pExpr;
     assert( pExpr!=0 );
     m |= pExpr->flags;

  }
  return m;
}

/*
** This is a SELECT-node callback for the expression walker that
** always "fails".  By "fail" in this case, we mean set

**  (22)  The subquery may not be a recursive CTE.
**
**  (23)  If the outer query is a recursive CTE, then the sub-query may not be
**        a compound query. This restriction is because transforming the
**        parent to a compound query confuses the code that handles
**        recursive queries in multiSelect().
**
**  (**)  We no longer attempt to flatten aggregate subqueries.  Was:
**        The subquery may not be an aggregate that uses the built-in min() or 
**        or max() functions.  (Without this restriction, a query like:
**        "SELECT x FROM (SELECT max(y), x FROM t1)" would not necessarily
**        return the value X for which Y was maximal.)
**
**
** In this routine, the "p" parameter is a pointer to the outer query.
** The subquery is p->pSrc->a[iFrom].  isAgg is true if the outer query

     return 0;                                           /* Restriction (11) */
  }
  if( isAgg && pSub->pOrderBy ) return 0;                /* Restriction (16) */
  if( pSub->pLimit && p->pWhere ) return 0;              /* Restriction (19) */
  if( pSub->pLimit && (p->selFlags & SF_Distinct)!=0 ){
     return 0;         /* Restriction (21) */
  }


  if( pSub->selFlags & (SF_Recursive) ){
    return 0; /* Restrictions (22) */
  }
  if( (p->selFlags & SF_Recursive) && pSub->pPrior ){
    return 0; /* Restriction (23) */
  }

  /*
  ** If the subquery is the right operand of a LEFT JOIN, then the

  Parse *pParse,        /* Parse context (for malloc() and error reporting) */
  Select *pSubq,        /* The subquery whose WHERE clause is to be augmented */
  Expr *pWhere,         /* The WHERE clause of the outer query */
  int iCursor           /* Cursor number of the subquery */
){
  Expr *pNew;
  int nChng = 0;

  if( pWhere==0 ) return 0;
  if( pSubq->selFlags & SF_Recursive ) return 0;  /* restriction (2) */

#ifdef SQLITE_DEBUG
  /* Only the first term of a compound can have a WITH clause.  But make
  ** sure no other terms are marked SF_Recursive in case something changes
  ** in the future.
  */
  {
    Select *pX;  
    for(pX=pSubq; pX; pX=pX->pPrior){
      assert( (pX->selFlags & (SF_Recursive))==0 );


    }
  }
#endif

  if( pSubq->pLimit!=0 ){
    return 0; /* restriction (3) */
  }
  while( pWhere->op==TK_AND ){
    nChng += pushDownWhereTerms(pParse, pSubq, pWhere->pRight, iCursor);
    pWhere = pWhere->pLeft;
  }

  2 "SELECT a, sum(b) FROM t1 GROUP BY a HAVING sum(b)>5 AND a=2"
    "SELECT a, sum(b) FROM t1 WHERE a=2 GROUP BY a HAVING sum(b)>5"

  3 "SELECT a, sum(b) FROM t1 GROUP BY a COLLATE binary HAVING a=2"
    "SELECT a, sum(b) FROM t1 WHERE a=2 GROUP BY a COLLATE binary"














  5 "SELECT a, sum(b) FROM t1 GROUP BY a COLLATE binary HAVING 0"
    "SELECT a, sum(b) FROM t1 WHERE 0 GROUP BY a COLLATE binary"

  6 "SELECT count(*) FROM t1,t2 WHERE a=c GROUP BY b, d HAVING b=d"
    "SELECT count(*) FROM t1,t2 WHERE a=c AND b=d GROUP BY b, d"

  7 {
      SELECT count(*) FROM t1,t2 WHERE a=c GROUP BY b, d 
      HAVING b=d COLLATE nocase
    } {
      SELECT count(*) FROM t1,t2 WHERE a=c AND b=d COLLATE nocase 
      GROUP BY b, d
    }

  8 "SELECT a, sum(b) FROM t1 GROUP BY a||b HAVING substr(a||b, 1, 1)='a'"
    "SELECT a, sum(b) FROM t1 WHERE substr(a||b, 1, 1)='a' GROUP BY a||b"
} {
  do_compare_vdbe_test 2.$tn $sql1 $sql2 1
}

# The (4) test in the above set used to generate identical bytecode, but
# that is no longer the case.  The byte code is equivalent, though.
#
do_execsql_test 2.4a {
  SELECT x,y FROM (
    SELECT a AS x, sum(b) AS y FROM t1 
    GROUP BY a
  ) WHERE x BETWEEN 2 AND 9999
} {2 12}
do_execsql_test 2.4b {
  SELECT x,y FROM (
    SELECT a AS x, sum(b) AS y FROM t1 
    WHERE x BETWEEN 2 AND 9999 
    GROUP BY a
  )
} {2 12}


#-------------------------------------------------------------------------
# 1: Test that the optimization is only applied if the GROUP BY term
#    uses BINARY collation.
#
# 2: Not applied if there is a non-deterministic function in the HAVING
#    term.