Merge spetrunia@bk-internal.mysql.com:/home/bk/mysql-5.0-opt

into  mysql.com:/home/psergey/mysql-5.0-bug31450

mysql-test/r/type_decimal.result

@@ -811,5 +811,14 @@ insert into t1 values (-0.123456,0.123456);
 select group_concat(f1),group_concat(f2) from t1;
 group_concat(f1)	group_concat(f2)
 -0.123456	0.123456
+create table t1 (
+ua_id decimal(22,0) not null,
+ua_invited_by_id decimal(22,0) default NULL,
+primary key(ua_id)
+);
+insert into t1 values (123, NULL), (456, NULL);
+this must not produce error 1048: 
+select * from t1 where ua_invited_by_id not in (select ua_id from t1);
+ua_id	ua_invited_by_id
 drop table t1;
 End of 5.0 tests

sql/item.cc

@@ -4551,7 +4551,7 @@ int Item::save_in_field(Field *field, bool no_conversions)
     my_decimal decimal_value;
     my_decimal *value= val_decimal(&decimal_value);
     if (null_value)
-      return set_field_to_null(field);
+      return set_field_to_null_with_conversions(field, no_conversions);
     field->set_notnull();
     error=field->store_decimal(value);
   }