Extension:GlobalUserrights/global_user_groups table

mysql> describe global_user_groups;
+------------+------------------+------+-----+---------+-------+
| Field      | Type             | Null | Key | Default | Extra |
+------------+------------------+------+-----+---------+-------+
| gug_user   | int(10) unsigned | NO   | PRI | 0       |       |
| gug_group  | varbinary(255)   | NO   | PRI |         |       |
| gug_expiry | varbinary(14)    | YES  | MUL | NULL    |       |
+------------+------------------+------+-----+---------+-------+