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Overview
Comment:When flattening a query of the form "SELECT * FROM (SELECT * FROM tbl WHERE x=?) WHERE y=?", ensure that the final WHERE clause is "x=? AND y=?" instead of "y=? AND x=?". Although it is still not guaranteed, this makes the order in which WHERE clause terms are processed comport more closely to users expectations.
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SHA1: cf7f9e6d5abff273dd2f8a8dce27d52e1449b3be
User & Date: dan 2016-09-26 14:39:05.023
Context
2016-09-27
00:03
Fix FTS3 test cases due to the flattener change of the previous check-in. (check-in: 0c8b9b211f user: drh tags: trunk)
2016-09-26
14:39
When flattening a query of the form "SELECT * FROM (SELECT * FROM tbl WHERE x=?) WHERE y=?", ensure that the final WHERE clause is "x=? AND y=?" instead of "y=? AND x=?". Although it is still not guaranteed, this makes the order in which WHERE clause terms are processed comport more closely to users expectations. (check-in: cf7f9e6d5a user: dan tags: trunk)
12:38
Inline the relevent parts of sqlite3ExprAlloc() into spanExpr(), for a performance improvement. (check-in: fe89225eab user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/select.c.
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      pSub->pOrderBy = 0;
    }
    pWhere = sqlite3ExprDup(db, pSub->pWhere, 0);
    if( subqueryIsAgg ){
      assert( pParent->pHaving==0 );
      pParent->pHaving = pParent->pWhere;
      pParent->pWhere = pWhere;
      pParent->pHaving = sqlite3ExprAnd(db, pParent->pHaving, 
                                  sqlite3ExprDup(db, pSub->pHaving, 0));

      assert( pParent->pGroupBy==0 );
      pParent->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy, 0);
    }else{
      pParent->pWhere = sqlite3ExprAnd(db, pParent->pWhere, pWhere);
    }
    substSelect(db, pParent, iParent, pSub->pEList, 0);
  
    /* The flattened query is distinct if either the inner or the
    ** outer query is distinct. 
    */
    pParent->selFlags |= pSub->selFlags & SF_Distinct;








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      pSub->pOrderBy = 0;
    }
    pWhere = sqlite3ExprDup(db, pSub->pWhere, 0);
    if( subqueryIsAgg ){
      assert( pParent->pHaving==0 );
      pParent->pHaving = pParent->pWhere;
      pParent->pWhere = pWhere;
      pParent->pHaving = sqlite3ExprAnd(db, 
          sqlite3ExprDup(db, pSub->pHaving, 0), pParent->pHaving
      );
      assert( pParent->pGroupBy==0 );
      pParent->pGroupBy = sqlite3ExprListDup(db, pSub->pGroupBy, 0);
    }else{
      pParent->pWhere = sqlite3ExprAnd(db, pWhere, pParent->pWhere);
    }
    substSelect(db, pParent, iParent, pSub->pEList, 0);
  
    /* The flattened query is distinct if either the inner or the
    ** outer query is distinct. 
    */
    pParent->selFlags |= pSub->selFlags & SF_Distinct;
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