Fix for Bug#5615 and merge from 4.1

mysql-test/r/func_group.result

@@ -669,12 +669,24 @@ select charset(max(a)), coercibility(max(a)),
 charset(min(a)), coercibility(min(a)) from t1;
 charset(max(a))	coercibility(max(a))	charset(min(a))	coercibility(min(a))
 latin2	2	latin2	2
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` char(1) character set latin2 default NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
 create table t2 select max(a),min(a) from t1;
 show create table t2;
 Table	Create Table
 t2	CREATE TABLE `t2` (
-  `max(a)` varchar(1) character set latin2 default NULL,
-  `min(a)` varchar(1) character set latin2 default NULL
+  `max(a)` char(1) character set latin2 default NULL,
+  `min(a)` char(1) character set latin2 default NULL
+) ENGINE=MyISAM DEFAULT CHARSET=latin1
+drop table t2;
+create table t2 select concat(a) from t1;
+show create table t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `concat(a)` varchar(1) character set latin2 default NULL
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t2,t1;
 create table t1 (a int);

mysql-test/r/show_check.result

@@ -252,11 +252,9 @@ type_bool	type_tiny	type_short	type_mediumint	type_bigint	type_decimal	type_nume
 drop table t1;
 create table t1 (a int not null);
 create table t2 select max(a) from t1;
-Warnings:
-Warning	1263	Data truncated; NULL supplied to NOT NULL column 'max(a)' at row 1
 show columns from t2;
 Field	Type	Null	Key	Default	Extra
-max(a)	int(11)			0	
+max(a)	int(11)	YES		NULL	
 drop table t1,t2;
 create table t1 (c decimal, d double, f float, r real);
 show columns from t1;

mysql-test/t/func_group.test

@@ -395,8 +395,12 @@ create table t1 (a char character set latin2);
 insert into t1 values ('a'),('b');
 select charset(max(a)), coercibility(max(a)),
        charset(min(a)), coercibility(min(a)) from t1;
+show create table t1;
 create table t2 select max(a),min(a) from t1;
 show create table t2;
+drop table t2;
+create table t2 select concat(a) from t1;
+show create table t2;
 drop table t2,t1;
 
 #

sql/item_sum.cc

@@ -22,6 +22,7 @@
 #endif
 
 #include "mysql_priv.h"
+#include "sql_select.h"
 
 Item_sum::Item_sum(List<Item> &list)
   :arg_count(list.elements)
@@ -303,6 +304,21 @@ Item_sum_hybrid::fix_fields(THD *thd, TABLE_LIST *tables, Item **ref)
   return FALSE;
 }
 
+Field *Item_sum_hybrid::create_tmp_field(bool group, TABLE *table,
+					 uint convert_blob_length)
+{
+  if (args[0]->type() == Item::FIELD_ITEM)
+  {
+    Field *field= ((Item_field*) args[0])->field;
+    
+    if ((field= create_tmp_field_from_field(current_thd, field, this, table,
+					    0, convert_blob_length)))
+      field->flags&= ~NOT_NULL_FLAG;
+    return field;
+  }
+  return Item_sum::create_tmp_field(group, table, convert_blob_length);
+}
+
 
 /***********************************************************************
 ** reset and add of sum_func
@@ -2075,8 +2091,6 @@ my_decimal *Item_variance_field::val_decimal(my_decimal *dec_buf)
 ** COUNT(DISTINCT ...)
 ****************************************************************************/
 
-#include "sql_select.h"
-
 int simple_str_key_cmp(void* arg, byte* key1, byte* key2)
 {
   Item_sum_count_distinct* item = (Item_sum_count_distinct*)arg;

sql/item_sum.h

@@ -94,7 +94,6 @@ public:
   Item *get_tmp_table_item(THD *thd);
   virtual Field *create_tmp_field(bool group, TABLE *table,
                                   uint convert_blob_length);
-
   bool walk (Item_processor processor, byte *argument);
 };
 
@@ -525,6 +524,8 @@ protected:
   void cleanup();
   bool any_value() { return was_values; }
   void no_rows_in_result();
+  Field *create_tmp_field(bool group, TABLE *table,
+			  uint convert_blob_length);
 };
 
 

sql/sql_select.cc

@@ -7593,10 +7593,10 @@ const_expression_in_where(COND *cond, Item *comp_item, Item **const_item)
     new_created field
 */
 
-static Field* create_tmp_field_from_field(THD *thd, Field* org_field,
-                                          Item *item, TABLE *table,
-                                          bool modify_item,
-                                          uint convert_blob_length)
+Field* create_tmp_field_from_field(THD *thd, Field* org_field,
+				   Item *item, TABLE *table,
+				   bool modify_item,
+				   uint convert_blob_length)
 {
   Field *new_field;
 

sql/sql_select.h

@@ -399,6 +399,10 @@ void copy_funcs(Item **func_ptr);
 bool create_myisam_from_heap(THD *thd, TABLE *table, TMP_TABLE_PARAM *param,
 			     int error, bool ignore_last_dupp_error);
 uint find_shortest_key(TABLE *table, const key_map *usable_keys);
+Field* create_tmp_field_from_field(THD *thd, Field* org_field,
+				   Item *item, TABLE *table,
+				   bool modify_item,
+				   uint convert_blob_length);
 
 /* functions from opt_sum.cc */
 bool simple_pred(Item_func *func_item, Item **args, bool *inv_order);