Why is signal keyword not working in mySQL 5.1.48?

mysql, mysql-5.1

Solution

As stated in the manual for MySQL version 5.1:

Other statements related to conditions are `SIGNAL`, `RESIGNAL`, and `GET DIAGNOSTICS`. The `SIGNAL` and `RESIGNAL` statements are not supported until MySQL 5.5. The `GET DIAGNOSTICS` statement is not supported until MySQL 5.6.

To raise an error in older versions of MySQL, just deliberately issue an erroneous command. I often `CALL` a non-existent procedure, for example:

CALL raise_error;

Problem

I'm using mysql v5.1.48 and red http://dev.mysql.com/doc/refman/5.5/en/signal.html. But the code ``` DELIMITER $$ CREATE PROCEDURE `CoreRaiseError`() BEGIN SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'An error occurred', MYSQL_ERRNO = 1001; END$$ ``` raise an SQL Error 1064: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SQLSTATE '45000' From which version SIGNAL start to be a keyword? How can I raise an exception with prior version of mysql? Thank you.

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