结果多于一行(More than one row as result)

结果多于一行(More than one row as result)

我做了以下过程，基本上是将两列中的一列“ not_good and good ”中的值传递到同一个表中的“ comment ”列，并使用等级值：

DELIMITER $$ CREATE OR REPLACE PROCEDURE add_comments() BEGIN DECLARE var INT; SELECT grade INTO var FROM table2; IF (var <= 7) THEN UPDATE table2 set comment = not_good; ELSE UPDATE table2 set comment = good; END IF; END$$ DELIMITER ;

当我CALL add_comentarios(); 我收到以下错误：

#1172 - Result consisted of more than one row

无法弄清楚如何使其工作，因为我想

PS：我是一个begginer rsrs

非常感谢任何答案！

I have the following procedure that I made to basically transfer the values from one of the two columns "not_good and good" to the column "comment" in the same table using the grade value:

DELIMITER $$ CREATE OR REPLACE PROCEDURE add_comments() BEGIN DECLARE var INT; SELECT grade INTO var FROM table2; IF (var <= 7) THEN UPDATE table2 set comment = not_good; ELSE UPDATE table2 set comment = good; END IF; END$$ DELIMITER ;

When I CALL add_comentarios(); I receive the following error:

#1172 - Result consisted of more than one row

Can't figure out how to make it work as I want

PS: I'm a begginer rsrs

Thanks a lot for any answer!

最满意答案

SELECT X INTO Y查询仅对单个结果查询有效; 由于您的查询从整个表中选择，因此只有当该表具有单个行时才有效。 无论如何，你正在试图做的事情可以用单个查询来完成....

UPDATE table2 SET comment = CASE WHEN grade <= 7 THEN 'not_good' ELSE 'good' END ;

SELECT X INTO Y queries are only valid for single result queries; since your query selects from the whole table, it would only be valid if the table had a single row. What you are trying to do can be done with a single query anyway....

UPDATE table2 SET comment = CASE WHEN grade <= 7 THEN 'not_good' ELSE 'good' END ;