MySQL5.6，使用SIGNAL可以根据变量的值，抛出Exception。

测试数据

create table t1(f1 int);

insert into t1(f1) values(2);

insert into t1(f1) values(12);

insert into t1(f1) values(4);

insert into t1(f1) values(6);

insert into t1(f1) values(7);

存储过程定义

-- --------------------------------------------------------------------------------

-- Routine DDL

-- Note: comments before and after the routine body will not be stored by the server

-- --------------------------------------------------------------------------------

DELIMITER $$

CREATE PROCEDURE `my_test`

 (

    in_c_t int

 )

BEGIN

 DECLARE my_n_t int;

 DECLARE specialty CONDITION FOR SQLSTATE '45000';

SELECT count(1) into my_n_t

    FROM t1

    WHERE f1 = in_c_t;

IF my_n_t = 0 THEN

    SIGNAL SQLSTATE '45000'

      SET MESSAGE_TEXT = 'Can not delete！';

end IF;

 delete from t1 WHERE f1 = in_c_t;

 COMMIT ;

END

执行

call my_test(2);

输出：