トリガーを入力した後、コンソールは通常のコマンドに応答しない奇妙な状態に見えます。うっかり区切り文字でそれをやっていますか?
mysql> use nntp;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> show tables;
+---------------------+
| Tables_in_nntp |
+---------------------+
| articles |
| newsgroups |
| newsgroups_articles |
+---------------------+
3 rows in set (0.00 sec)
mysql> show triggers;
Empty set (0.00 sec)
mysql> DELIMITER $$
mysql> USE `nntp`$$
Database changed
mysql> CREATE
-> TRIGGER `nntp.newsgroups.before_insert`
-> BEFORE INSERT ON `nntp`.`newsgroups`
-> FOR EACH ROW
-> BEGIN
-> set new.hash = md5(new.newsgroup);
-> END$$
Query OK, 0 rows affected (0.18 sec)
mysql> DELIMITER $$
mysql> USE `nntp`$$
Database changed
mysql> CREATE
-> TRIGGER `nntp.newsgroups.before_update`
-> BEFORE UPDATE ON `nntp`.`newsgroups`
-> FOR EACH ROW
-> BEGIN
-> set new.hash = md5(new.newsgroup);
-> END$$
Query OK, 0 rows affected (0.19 sec)
mysql> show triggers;
-> ^CCtrl-C -- exit!
Aborted
thufir@dur:~$