Merge macbook.gmz:/Users/kgeorge/mysql/work/B33256-5.0-opt

into  macbook.gmz:/Users/kgeorge/mysql/work/B33256-5.1-opt

mysql-test/r/type_decimal.result

@@ -786,10 +786,6 @@ from (select 1 as s,'t' as t union select null, null ) as sub1;
 select group_concat(t) from t1 group by week(date)/10;
 group_concat(t)
 t
-Warnings:
-Warning	1292	Incorrect datetime value: '0000-00-00'
-Warning	1292	Incorrect datetime value: '0000-00-00'
-Warning	1292	Incorrect datetime value: '0000-00-00'
 drop table t1;
 CREATE TABLE t1 (
 qty decimal(16,6) default NULL, 

sql/field.h

@@ -1269,6 +1269,10 @@ public:
     :Field_str(ptr_arg, 10, null_ptr_arg, null_bit_arg,
 	       unireg_check_arg, field_name_arg, cs)
     {}
+  Field_newdate(bool maybe_null_arg, const char *field_name_arg,
+                struct st_table *table_arg, CHARSET_INFO *cs)
+    :Field_str((char*) 0,10, maybe_null_arg ? (uchar*) "": 0,0,
+               NONE, field_name_arg, table_arg, cs) {}
   enum_field_types type() const { return MYSQL_TYPE_DATE;}
   enum_field_types real_type() const { return MYSQL_TYPE_NEWDATE; }
   enum ha_base_keytype key_type() const { return HA_KEYTYPE_UINT24; }

sql/item.cc

@@ -4467,7 +4467,7 @@ Field *Item::tmp_table_field_from_field_type(TABLE *table, bool fixed_length)
     break;
   case MYSQL_TYPE_NEWDATE:
   case MYSQL_TYPE_DATE:
-    field= new Field_date(maybe_null, name, &my_charset_bin);
+    field= new Field_newdate(maybe_null, name, &my_charset_bin);
     break;
   case MYSQL_TYPE_TIME:
     field= new Field_time(maybe_null, name, &my_charset_bin);

sql/item_sum.cc

@@ -633,7 +633,7 @@ Field *Item_sum_hybrid::create_tmp_field(bool group, TABLE *table,
   */
   switch (args[0]->field_type()) {
   case MYSQL_TYPE_DATE:
-    field= new Field_date(maybe_null, name, collation.collation);
+    field= new Field_newdate(maybe_null, name, collation.collation);
     break;
   case MYSQL_TYPE_TIME:
     field= new Field_time(maybe_null, name, collation.collation);