Question

我尝试了两种方法来重复一些语法正确的代码，但似乎循环（既不是LOOP也不是WHILE）都无法执行。

1使用WHILE：

SET @y =1;
DROP PROCEDURE IF EXISTS parm_y;
DELIMITER //
CREATE PROCEDURE parm_y()
BEGIN
WHILE @y != 62 DO //stop condition
INSERT INTO parm_y SELECT * FROM tempff WHERE op0=@y LIMIT 1;// repeating work 
SELECT addr INTO @y FROM tempff WHERE op0=@y LIMIT 1; // repeating work 
END WHILE;
END //
DELIMITER ;

2使用LOOP：

SET @y =1;
DROP PROCEDURE IF EXISTS parm_y;
DELIMITER //
CREATE PROCEDURE parm_y()
BEGIN
y_loop: LOOP
INSERT INTO parm_y SELECT * FROM tempff WHERE op0=@y LIMIT 1; // repeating work 
SELECT addr INTO @y FROM tempff WHERE op0=@y LIMIT 1; //repeating work
IF @y = 62 THEN //stop condition
LEAVE y_loop;
END IF;
END LOOP;
END //
DELIMITER ;

我不想手动重复这两行。这两段的语法都是正确的。但是没有一个进入循环。

任何人都可以帮助我吗？非常感谢你。

Answer 1

问题是你没有递增你的计数器@y。它应该像

SET @y =1; 

DROP PROCEDURE IF EXISTS parm_y; DELIMITER // CREATE PROCEDURE parm_y() 

BEGIN 

WHILE @y < 62 DO //stop condition (changed from `!=` to `<`)

INSERT INTO parm_y SELECT * FROM tempff WHERE op0=@y LIMIT 1;// repeating work 

SELECT addr INTO @y FROM tempff WHERE op0=@y LIMIT 1; // repeating work 

SET @y = @y + 1; // Missing this part

END WHILE; 

END 

// DELIMITER ;

mysql，LOOP或WHILE不能重复。

1 个答案: