Bug#12329653 - EXPLAIN, UNION, PREPARED STATEMENT, CRASH, SQL_FULL_GROUP_BY

The query was re-written *after* we had tagged it with NON_AGG_FIELD_USED.
Remove the flag before continuing.


mysql-test/r/explain.result:
  Update test case for Bug#48295.
mysql-test/r/subselect.result:
  New test case.
mysql-test/t/explain.test:
  Update test case for Bug#48295.
mysql-test/t/subselect.test:
  New test case.
sql/item.cc:
  Use accessor functions for non_agg_field_used/agg_func_used.
sql/item_subselect.cc:
  Remove non_agg_field_used when we rewrite query '1 < some (...)' => '1 < max(...)'
sql/item_sum.cc:
  Use accessor functions for non_agg_field_used/agg_func_used.
sql/mysql_priv.h:
  Remove unused #defines.
sql/sql_lex.cc:
  Initialize new member variables.
sql/sql_lex.h:
  Replace full_group_by_flag with two boolean flags,
  and itroduce accessors for manipulating them.
sql/sql_select.cc:
  Use accessor functions for non_agg_field_used/agg_func_used.

mysql-test/r/explain.result

@@ -176,11 +176,12 @@ SELECT @@session.sql_mode INTO @old_sql_mode;
 SET SESSION sql_mode='ONLY_FULL_GROUP_BY';
 EXPLAIN EXTENDED SELECT 1 FROM t1
 WHERE f1 > ALL( SELECT t.f1 FROM t1,t1 AS t );
-ERROR 42000: Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause
-SHOW WARNINGS;
-Level	Code	Message
-Error	1140	Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause
-Note	1003	select 1 AS `1` from `test`.`t1` where <not>(<exists>(...))
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	SUBQUERY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
+2	SUBQUERY	t	system	NULL	NULL	NULL	NULL	0	const row not found
+Warnings:
+Note	1003	select 1 AS `1` from `test`.`t1` where 0
 SET SESSION sql_mode=@old_sql_mode;
 DROP TABLE t1;
 End of 5.0 tests.

mysql-test/r/subselect.result

@@ -4528,6 +4528,32 @@ pk	int_key
 7	3
 DROP TABLE t1,t2;
 #
+# Bug#12329653 
+# EXPLAIN, UNION, PREPARED STATEMENT, CRASH, SQL_FULL_GROUP_BY
+#
+CREATE TABLE t1(a1 int);
+INSERT INTO t1 VALUES (1),(2);
+SELECT @@session.sql_mode INTO @old_sql_mode;
+SET SESSION sql_mode='ONLY_FULL_GROUP_BY';
+SELECT 1 FROM t1 WHERE 1 < SOME (SELECT a1 FROM t1);
+1
+1
+1
+PREPARE stmt FROM 
+'SELECT 1 UNION ALL 
+SELECT 1 FROM t1
+ORDER BY
+(SELECT 1 FROM t1 AS t1_0  
+  WHERE 1 < SOME (SELECT a1 FROM t1)
+)' ;
+EXECUTE stmt ;
+ERROR 21000: Subquery returns more than 1 row
+EXECUTE stmt ;
+ERROR 21000: Subquery returns more than 1 row
+SET SESSION sql_mode=@old_sql_mode;
+DEALLOCATE PREPARE stmt;
+DROP TABLE t1;
+#
 # Bug #52711: Segfault when doing EXPLAIN SELECT with 
 #  union...order by (select... where...)
 #

mysql-test/t/explain.test

 #
-# Test of different EXPLAIN's
+# Test of different EXPLAINs
 
 --disable_warnings
 drop table if exists t1;
@@ -157,11 +157,12 @@ CREATE TABLE t1 (f1 INT);
 SELECT @@session.sql_mode INTO @old_sql_mode;
 SET SESSION sql_mode='ONLY_FULL_GROUP_BY';
 
-# EXPLAIN EXTENDED (with subselect). used to crash. should give NOTICE.
---error ER_MIX_OF_GROUP_FUNC_AND_FIELDS
+# EXPLAIN EXTENDED (with subselect). used to crash.
+# This is actually a valid query for this sql_mode,
+# but it was transformed in such a way that it failed, see
+# Bug#12329653 - EXPLAIN, UNION, PREPARED STATEMENT, CRASH, SQL_FULL_GROUP_BY
 EXPLAIN EXTENDED SELECT 1 FROM t1
                           WHERE f1 > ALL( SELECT t.f1 FROM t1,t1 AS t );
-SHOW WARNINGS;
 
 SET SESSION sql_mode=@old_sql_mode;
 

mysql-test/t/subselect.test

@@ -3506,6 +3506,40 @@ ORDER BY outr.pk;
 
 DROP TABLE t1,t2;
 
+--echo #
+--echo # Bug#12329653 
+--echo # EXPLAIN, UNION, PREPARED STATEMENT, CRASH, SQL_FULL_GROUP_BY
+--echo #
+
+CREATE TABLE t1(a1 int);
+INSERT INTO t1 VALUES (1),(2);
+
+SELECT @@session.sql_mode INTO @old_sql_mode;
+SET SESSION sql_mode='ONLY_FULL_GROUP_BY';
+
+## First a simpler query, illustrating the transformation
+## '1 < some (...)' => '1 < max(...)'
+SELECT 1 FROM t1 WHERE 1 < SOME (SELECT a1 FROM t1);
+
+## The query which made the server crash.
+PREPARE stmt FROM 
+'SELECT 1 UNION ALL 
+SELECT 1 FROM t1
+ORDER BY
+(SELECT 1 FROM t1 AS t1_0  
+  WHERE 1 < SOME (SELECT a1 FROM t1)
+)' ;
+
+--error ER_SUBQUERY_NO_1_ROW
+EXECUTE stmt ;
+--error ER_SUBQUERY_NO_1_ROW
+EXECUTE stmt ;
+
+SET SESSION sql_mode=@old_sql_mode;
+
+DEALLOCATE PREPARE stmt;
+DROP TABLE t1;
+
 --echo #
 --echo # Bug #52711: Segfault when doing EXPLAIN SELECT with 
 --echo #  union...order by (select... where...)

sql/item.cc

@@ -4080,14 +4080,14 @@ bool Item_field::fix_fields(THD *thd, Item **reference)
       aggregated or not.
     */
     if (!thd->lex->in_sum_func)
-      cached_table->select_lex->full_group_by_flag|= NON_AGG_FIELD_USED;
+      cached_table->select_lex->set_non_agg_field_used(true);
     else
     {
       if (outer_fixed)
         thd->lex->in_sum_func->outer_fields.push_back(this);
       else if (thd->lex->in_sum_func->nest_level !=
           thd->lex->current_select->nest_level)
-        cached_table->select_lex->full_group_by_flag|= NON_AGG_FIELD_USED;
+        cached_table->select_lex->set_non_agg_field_used(true);
     }
   }
   return FALSE;

sql/item_subselect.cc

@@ -936,6 +936,14 @@ Item_in_subselect::single_value_transformer(JOIN *join,
 	it.replace(item);
       }
 
+      DBUG_EXECUTE("where",
+                   print_where(item, "rewrite with MIN/MAX"););
+      if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY)
+      {
+        DBUG_ASSERT(select_lex->non_agg_field_used());
+        select_lex->set_non_agg_field_used(false);
+      }
+
       save_allow_sum_func= thd->lex->allow_sum_func;
       thd->lex->allow_sum_func|= 1 << thd->lex->current_select->nest_level;
       /*

sql/item_sum.cc

@@ -246,10 +246,10 @@ bool Item_sum::check_sum_func(THD *thd, Item **ref)
           in_sum_func->outer_fields.push_back(field);
         }
         else
-          sel->full_group_by_flag|= NON_AGG_FIELD_USED;
+          sel->set_non_agg_field_used(true);
       }
       if (sel->nest_level > aggr_level &&
-          (sel->full_group_by_flag & SUM_FUNC_USED) &&
+          (sel->agg_func_used()) &&
           !sel->group_list.elements)
       {
         my_message(ER_MIX_OF_GROUP_FUNC_AND_FIELDS,
@@ -258,7 +258,7 @@ bool Item_sum::check_sum_func(THD *thd, Item **ref)
       }
     }
   }
-  aggr_sel->full_group_by_flag|= SUM_FUNC_USED;
+  aggr_sel->set_agg_func_used(true);
   update_used_tables();
   thd->lex->in_sum_func= in_sum_func;
   return FALSE;

sql/mysql_priv.h

@@ -1086,13 +1086,6 @@ SQL_SELECT *make_select(TABLE *head, table_map const_tables,
                         bool allow_null_cond,  int *error);
 extern Item **not_found_item;
 
-/*
-  A set of constants used for checking non aggregated fields and sum
-  functions mixture in the ONLY_FULL_GROUP_BY_MODE.
-*/
-#define NON_AGG_FIELD_USED  1
-#define SUM_FUNC_USED       2
-
 /*
   This enumeration type is used only by the function find_item_in_list
   to return the info on how an item has been resolved against a list

sql/sql_lex.cc

@@ -1232,6 +1232,8 @@ void st_select_lex::init_query()
   exclude_from_table_unique_test= no_wrap_view_item= FALSE;
   nest_level= 0;
   link_next= 0;
+  m_non_agg_field_used= false;
+  m_agg_func_used= false;
 }
 
 void st_select_lex::init_select()
@@ -1266,7 +1268,8 @@ void st_select_lex::init_select()
   non_agg_fields.empty();
   cond_value= having_value= Item::COND_UNDEF;
   inner_refs_list.empty();
-  full_group_by_flag= 0;
+  m_non_agg_field_used= false;
+  m_agg_func_used= false;
 }
 
 /*

sql/sql_lex.h

@@ -617,16 +617,7 @@ class st_select_lex: public st_select_lex_node
     joins on the right.
   */
   List<String> *prev_join_using;
-  /*
-    Bitmap used in the ONLY_FULL_GROUP_BY_MODE to prevent mixture of aggregate
-    functions and non aggregated fields when GROUP BY list is absent.
-    Bits:
-      0 - non aggregated fields are used in this select,
-          defined as NON_AGG_FIELD_USED.
-      1 - aggregate functions are used in this select,
-          defined as SUM_FUNC_USED.
-  */
-  uint8 full_group_by_flag;
+
   void init_query();
   void init_select();
   st_select_lex_unit* master_unit();
@@ -714,6 +705,21 @@ class st_select_lex: public st_select_lex_node
     select lexes.
   */
   void cleanup_all_joins(bool full);
+  /*
+    For MODE_ONLY_FULL_GROUP_BY we need to maintain two flags:
+     - Non-aggregated fields are used in this select.
+     - Aggregate functions are used in this select.
+    In MODE_ONLY_FULL_GROUP_BY only one of these may be true.
+  */
+  bool non_agg_field_used() const { return m_non_agg_field_used; }
+  bool agg_func_used()      const { return m_agg_func_used; }
+
+  void set_non_agg_field_used(bool val) { m_non_agg_field_used= val; }
+  void set_agg_func_used(bool val)      { m_agg_func_used= val; }
+
+private:
+  bool m_non_agg_field_used;
+  bool m_agg_func_used;
 };
 typedef class st_select_lex SELECT_LEX;
 

sql/sql_select.cc

@@ -391,19 +391,18 @@ inline int setup_without_group(THD *thd, Item **ref_pointer_array,
   int res;
   nesting_map save_allow_sum_func=thd->lex->allow_sum_func ;
   /* 
-    Need to save the value, so we can turn off only the new NON_AGG_FIELD
+    Need to save the value, so we can turn off only any new non_agg_field_used
     additions coming from the WHERE
   */
-  uint8 saved_flag= thd->lex->current_select->full_group_by_flag;
+  const bool saved_non_agg_field_used=
+    thd->lex->current_select->non_agg_field_used();
   DBUG_ENTER("setup_without_group");
 
   thd->lex->allow_sum_func&= ~(1 << thd->lex->current_select->nest_level);
   res= setup_conds(thd, tables, leaves, conds);
 
   /* it's not wrong to have non-aggregated columns in a WHERE */
-  if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY)
-    thd->lex->current_select->full_group_by_flag= saved_flag |
-      (thd->lex->current_select->full_group_by_flag & ~NON_AGG_FIELD_USED);
+  thd->lex->current_select->set_non_agg_field_used(saved_non_agg_field_used);
 
   thd->lex->allow_sum_func|= 1 << thd->lex->current_select->nest_level;
   res= res || setup_order(thd, ref_pointer_array, tables, fields, all_fields,
@@ -593,7 +592,8 @@ JOIN::prepare(Item ***rref_pointer_array,
     aggregate functions with implicit grouping (there is no GROUP BY).
   */
   if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY && !group_list &&
-      select_lex->full_group_by_flag == (NON_AGG_FIELD_USED | SUM_FUNC_USED))
+      select_lex->non_agg_field_used() &&
+      select_lex->agg_func_used())
   {
     my_message(ER_MIX_OF_GROUP_FUNC_AND_FIELDS,
                ER(ER_MIX_OF_GROUP_FUNC_AND_FIELDS), MYF(0));