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Description

This error signifies an attempt to create a MySQL event using a name that is already in use within the database server. It typically occurs when a `CREATE EVENT` statement is executed for an event that has previously been defined and not dropped.

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Error Message

Event '%s' already exists

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Known Causes

3 known causes

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Attempted Duplicate Creation

A `CREATE EVENT` statement was executed, but an event with the specified name already exists in the current MySQL server instance.

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Script Rerun Without Cleanup

During a redeployment or a rerun of a setup script, the script attempted to create an event that was not dropped from a previous execution.

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Unaware Name Collision

A new event was defined with a chosen name that unknowingly matches an existing event in the database, leading to a naming conflict.

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Solutions

3 solutions available

1. Drop and Recreate the Event easy

Remove the existing event and then create it again with the same definition.

1

Connect to your MySQL server using a client like `mysql` command-line or a GUI tool.

2

Identify the exact name of the event that is causing the error. The error message will typically show this name in place of '%s'. Let's assume the event name is `my_scheduled_task`.

3

Execute a `DROP EVENT` statement to remove the existing event.

DROP EVENT IF EXISTS my_scheduled_task;

4

Now, execute your original `CREATE EVENT` statement to recreate the event.

CREATE EVENT my_scheduled_task
ON SCHEDULE EVERY 1 DAY STARTS CURRENT_TIMESTAMP + INTERVAL 1 HOUR
DO
  -- Your SQL statements here
  SELECT 1;

2. Verify Event Existence Before Creation medium

Add a check to see if an event already exists before attempting to create it.

1

When you are creating the event, wrap your `CREATE EVENT` statement within a conditional block that checks for the event's existence.

DELIMITER $$

CREATE EVENT IF NOT EXISTS my_scheduled_task
ON SCHEDULE EVERY 1 DAY STARTS CURRENT_TIMESTAMP + INTERVAL 1 HOUR
DO
  -- Your SQL statements here
  SELECT 1; $$ 

DELIMITER ;

2

Alternatively, you can use a stored procedure or a script that performs this check.

SET @event_name = 'my_scheduled_task';

SELECT COUNT(*) INTO @event_exists
FROM information_schema.events
WHERE EVENT_SCHEMA = DATABASE() AND EVENT_NAME = @event_name;

IF @event_exists = 0 THEN
  -- Construct and execute your CREATE EVENT statement here
  -- Example:
  PREPARE stmt FROM 'CREATE EVENT my_scheduled_task ON SCHEDULE EVERY 1 DAY STARTS CURRENT_TIMESTAMP + INTERVAL 1 HOUR DO SELECT 1;';
  EXECUTE stmt;
  DEALLOCATE PREPARE stmt;
ELSE
  SELECT CONCAT('Event ', @event_name, ' already exists. Skipping creation.') AS Message;
END IF;

3. Inspect and Manage Existing Events easy

Use `SHOW EVENTS` to identify and manage events that are already scheduled.

1

Connect to your MySQL server.

2

Run the `SHOW EVENTS` command to list all scheduled events in the current database.

SHOW EVENTS;

3

Review the output to find the event that is causing the conflict. Note its name.

4

If you intend to replace the existing event, use the `DROP EVENT` command followed by your `CREATE EVENT` statement, as described in the first solution.

DROP EVENT event_name;
CREATE EVENT event_name ...;

5

If the event is no longer needed, you can simply drop it.

DROP EVENT event_name;

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Related Errors

5 related errors

MySQL Error 1537: Event Already Exists