Question

来自@Shaharsh Shah的代码：

DELIMITER $$

DROP TRIGGER /*!50032 IF EXISTS */ trig_auto_spid$$

CREATE
/*!50017 DEFINER = 'root'@'localhost' */
TRIGGER `trig_auto_spid` AFTER INSERT ON `tapes` 
FOR EACH ROW BEGIN
    SELECT REPLACE(TSpecID, 'TS', '') INTO @counter 
    FROM Tape_Specific_ID 
    ORDER BY TSpecID DESC LIMIT 1;

    SET loopCnt = @counter + new.qty; 
    WHILE (@counter <= loopCnt) DO 
        INSERT INTO Tape_Specific_ID(TapesID, TSpecID) 
        VALUES (new.TapesID, CONCAT('TS', @counter)); 
        SET @counter:=@counter + 1;
    END WHILE; 
END;
$$

DELIMITER ;

创建此触发器时发生错误错误1193（HY00）：Uknown系统变量'loopCnt'，为什么？有什么帮助吗？

Answer 1

将其设为user variable

SET @loopCnt := @counter + new.qty; 
WHILE (@counter <= @loopCnt) DO

更新1

SET @counter := 10;
SET @loopCnt := @counter + new.qty; 
WHILE (@counter <= @loopCnt) DO

Answer 2

尝试

SET @loopCnt = @counter + new.qty; 
WHILE (@counter <= @loopCnt) DO

用户定义的变量需要前面有一个@，否则它认为它是系统的一个变量，它没有定义。

mysql错误1193（HY00）：Uknown系统变量'loopCnt'

2 个答案: