从表中删除数据时收到错误＃1242

Question

我正在尝试从表中删除数据，我的查询如下：

delete from mybadge where uid=5 and badge_name=(select concat(tag_name,'-Beginner') from tag,post_tags where post_tags.tag_id=tag.tag_id);

我通过select语句得到5条记录，我想删除所有5条记录。

Answer 1

在关键字中使用 - '而不是'='符号

delete from mybadge where uid=5 and badge_name in (select concat(tag_name,'-Beginner') from tag,post_tags where post_tags.tag_id=tag.tag_id);

Answer 2

如您所述，您的子查询返回5行。 但是，badge_name在同一行中不能有5个不同的值。这有点像说：

 delete from mybadge where uid=5 and badge_name=(5 different values)

试

delete from mybadge where uid=5 and badge_name in (select concat(tag_name,'-Beginner') from tag,post_tags where post_tags.tag_id=tag.tag_id);

Answer 3

如果select语句对你有效，那么只需删除select：

返回的所有uid

DELETE FROM mybadge WHERE uid IN(
SELECT uid
FROM mybadge 
WHERE uid=5 
AND badge_name=(SELECT concat(tag_name,'-Beginner') 
                FROM tag,post_tags 
                WHERE post_tags.tag_id=tag.tag_id)
);