如何抑制MySQL中的警告？

Mysql> SET sql_notes = 1;
Query OK, 0 rows affected (0.00 sec)

mysql> drop table if exists WEB.DemoTable;
Query OK, 0 rows affected, 1 warning (0.07 sec)

mysql> show warnings;

+-------+------+-----------------------------------+
| Level | Code | Message                           |
+-------+------+-----------------------------------+
| Note  | 1051 | Unknown table 'web.DemoTable'     |
+-------+------+-----------------------------------+
1 row in set (0.00 sec)

mysql> SET sql_notes = 0;
Query OK, 0 rows affected (0.00 sec)

mysql> drop table if exists web.DemoTable;
Query OK, 0 rows affected (0.07 sec)

mysql> show warnings;
Empty set (0.00 sec)