Delete trigger if it exists in MySQL?

To delete a trigger, use the DROP command. The syntax is as follows −

DROP TRIGGER IF EXISTS yourTriggerName;

In order to understand the above syntax, you need to have a trigger in the current database.

To check if a trigger exists, you can use the following query. We have a trigger in our database −

mysql> show triggers;

The following is the output −

+-------------+--------+---------------+------------------------------------------------------------------------+--------+------------------------+--------------------------------------------+---------+----------------------+----------------------+--------------------+
| Trigger     | Event   | Table        | Statement                                                              | Timing |Created                 | sql_mode                                   |  Definer                 | character_set_client | collation_connection | Database Collation |
+-------------+--------+---------------+------------------------------------------------------------------------+--------+------------------------+--------------------------------------------+---------+----------------------+----------------------+--------------------+
| CheckSalary | INSERT | employeetable | if new.EmployeeSalary < 1000 then setnew.EmployeeSalary = 10000;end if | BEFORE | 2018-12-31 17:33:29.54 |STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION | root@% | utf8 |utf8_general_ci | utf8mb4_0900_ai_ci |
+-------------+--------+---------------+------------------------------------------------------------------------+--------+------------------------+--------------------------------------------+---------+----------------------+----------------------+--------------------+
1 row in set (0.17 sec)

Here, we have a trigger named 'CheckSalary' on the employeetable. Use the DROP command to remove trigger 'CheckSalary'. The query is as follows -

mysql> drop trigger if exists CheckSalary;
Query OK, 0 rows affected (0.30 sec)

Use the show triggers command to check whether the trigger exists. The query is as follows −

mysql> show triggers;
Empty set (0.00 sec)

Now look at the above results, the trigger does not exist in the database "test". We use drop to delete it.

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