mysql> use evdb
Database changed
mysql> select * from regdown;
+----+--------+
| id | nId    |
+----+--------+
|  1 | 469180 |
+----+--------+
1 row in set (0.00 sec)

mysql> update regdown set nId=0;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0