mysql - 为什么 signal 关键字在 mySQL 5.1.48 中不起作用？

Question

我正在使用 mysql v5.1.48 和红色 http://dev.mysql.com/doc/refman/5.5/en/signal.html .但是代码

DELIMITER $$
CREATE PROCEDURE `CoreRaiseError`()
BEGIN
  SIGNAL SQLSTATE '45000'
      SET MESSAGE_TEXT = 'An error occurred', MYSQL_ERRNO = 1001;
END$$

提出一个

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'

SIGNAL从哪个版本开始成为关键字？我怎样才能用以前版本的 mysql 引发异常？

谢谢。

Answer 1

如 the manual 中所述对于 MySQL 5.1 版:

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.

要在旧版本的 MySQL 中引发错误，只需故意发出错误的命令即可。我经常CALL一个不存在的过程，例如:

CALL raise_error;