RAISE_ERROR Function

raise_error(message)

Description

The RAISE_ERROR function throws a runtime error during query execution and aborts the query. This function accepts an error message string as a parameter. When the function is executed, it throws an exception and displays the specified error message. It is often used in combination with the IF function to terminate query execution when specific conditions are met.

Parameters

• message: STRING type, the error message content. If the parameter is NULL, "null message" is displayed.

Return Type

• This function does not return a normal value.
• Throws an exception and aborts the query upon execution.
• The error message includes the provided message parameter.

Notes

• This function aborts query execution and should be used with caution.
• When used in production environments, ensure it is only triggered in necessary validation scenarios.
• Error messages should be clear and explicit for easier troubleshooting.
• A NULL parameter will display "null message"; avoid passing NULL.

Examples

1. Combined with IF: conditional error checking

SELECT IF(COUNT(*) > 0, raise_error('error_result'), 6666)
FROM (SELECT 1 WHERE 1 = 0);
+---------------------------------------------------------+
| IF(COUNT(*) > 0, raise_error('error_result'), 6666)     |
+---------------------------------------------------------+
| 6666                                                    |
+---------------------------------------------------------+

2. Using in CASE WHEN

SELECT
  CASE
    WHEN status = 'active' THEN 'Active'
    WHEN status = 'inactive' THEN 'Inactive'
    ELSE raise_error('Unknown status: ' || status)
  END as status_label
FROM user_status;