Merge rurik.mysql.com:/home/igor/mysql-5.0

into  rurik.mysql.com:/home/igor/dev/mysql-5.0-0

mysql-test/r/having.result

@@ -141,6 +141,23 @@ SUM(a)
 6
 4
 DROP TABLE t1;
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (1), (2), (1), (3), (2), (1);
+SELECT a FROM t1 GROUP BY a HAVING a > 1;
+a
+2
+3
+SELECT a FROM t1 GROUP BY a HAVING 1 != 1 AND a > 1;
+a
+SELECT 0 AS x, a FROM t1 GROUP BY x,a HAVING x=1 AND a > 1;
+x	a
+EXPLAIN SELECT a FROM t1 GROUP BY a HAVING 1 != 1 AND a > 1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible HAVING
+EXPLAIN SELECT 0 AS x, a FROM t1 GROUP BY x,a HAVING x=1 AND a > 1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible HAVING
+DROP table t1;
 create table t1 (col1 int, col2 varchar(5), col_t1 int);
 create table t2 (col1 int, col2 varchar(5), col_t2 int);
 create table t3 (col1 int, col2 varchar(5), col_t3 int);

mysql-test/t/having.test

@@ -135,6 +135,22 @@ SELECT SUM(a) FROM t1 GROUP BY a HAVING SUM(a);
 
 DROP TABLE t1;
 
+#
+# Bug #14927: HAVING clause containing constant false conjunct
+#
+
+CREATE TABLE t1 (a int);
+INSERT INTO t1 VALUES (1), (2), (1), (3), (2), (1);
+
+SELECT a FROM t1 GROUP BY a HAVING a > 1;
+SELECT a FROM t1 GROUP BY a HAVING 1 != 1 AND a > 1;
+SELECT 0 AS x, a FROM t1 GROUP BY x,a HAVING x=1 AND a > 1;
+
+EXPLAIN SELECT a FROM t1 GROUP BY a HAVING 1 != 1 AND a > 1;
+EXPLAIN SELECT 0 AS x, a FROM t1 GROUP BY x,a HAVING x=1 AND a > 1;
+
+DROP table t1;  
+
 # End of 4.1 tests
 
 #

sql/sql_lex.cc

@@ -1122,7 +1122,7 @@ void st_select_lex::init_query()
   embedding= leaf_tables= 0;
   item_list.empty();
   join= 0;
-  having= where= prep_where= 0;
+  having= prep_having= where= prep_where= 0;
   olap= UNSPECIFIED_OLAP_TYPE;
   having_fix_field= 0;
   context.select_lex= this;

sql/sql_lex.h

@@ -474,6 +474,7 @@ public:
   char *db;
   Item *where, *having;                         /* WHERE & HAVING clauses */
   Item *prep_where; /* saved WHERE clause for prepared statement processing */
+  Item *prep_having;/* saved HAVING clause for prepared statement processing */
   /* point on lex in which it was created, used in view subquery detection */
   st_lex *parent_lex;
   enum olap_type olap;

sql/sql_prepare.cc

@@ -2066,13 +2066,18 @@ void reinit_stmt_before_use(THD *thd, LEX *lex)
       sl->exclude_from_table_unique_test= FALSE;
 
       /*
-        Copy WHERE clause pointers to avoid damaging they by optimisation
+        Copy WHERE, HAVING clause pointers to avoid damaging them by optimisation
       */
      if (sl->prep_where)
      {
        sl->where= sl->prep_where->copy_andor_structure(thd);
        sl->where->cleanup();
      }
+     if (sl->prep_having)
+     {
+       sl->having= sl->prep_having->copy_andor_structure(thd);
+       sl->having->cleanup();
+     }
      DBUG_ASSERT(sl->join == 0);
       ORDER *order;
       /* Fix GROUP list */

sql/sql_select.cc

@@ -612,6 +612,7 @@ JOIN::optimize()
     build_bitmap_for_nested_joins(join_list, 0);
 
     sel->prep_where= conds ? conds->copy_andor_structure(thd) : 0;
+    sel->prep_having= having ? having->copy_andor_structure(thd) : 0;
 
     if (arena)
       thd->restore_active_arena(arena, &backup);
@@ -625,14 +626,27 @@ JOIN::optimize()
     DBUG_RETURN(1);
   }
 
-  if (cond_value == Item::COND_FALSE ||
+  {
+    Item::cond_result having_value;
+    having= optimize_cond(this, having, join_list, &having_value);
+    if (thd->net.report_error)
+    {
+      error= 1;
+      DBUG_PRINT("error",("Error from optimize_cond"));
+      DBUG_RETURN(1);
+    }
+
+    if (cond_value == Item::COND_FALSE || having_value == Item::COND_FALSE || 
         (!unit->select_limit_cnt && !(select_options & OPTION_FOUND_ROWS)))
     {						/* Impossible cond */
-    DBUG_PRINT("info", ("Impossible WHERE"));
-    zero_result_cause= "Impossible WHERE";
+      DBUG_PRINT("info", (having_value == Item::COND_FALSE ? 
+                            "Impossible HAVING" : "Impossible WHERE"));
+      zero_result_cause=  having_value == Item::COND_FALSE ?
+                           "Impossible HAVING" : "Impossible WHERE";
       error= 0;
       DBUG_RETURN(0);
     }
+  }
 
   /* Optimize count(*), min() and max() */
   if (tables_list && tmp_table_param.sum_func_count && ! group_list)