我有一个评论表,其结构如下:
id, name, email, comment
我有很多重复的评论,同名和电子邮件。我需要删除它们,任何人都可以建议我如何使用单个查询实现此目的?
由于
答案 0 :(得分:7)
DELETE FROM comments c1
WHERE EXISTS (
SELECT *
FROM comments c2
WHERE c2.id <> c1.id
AND c2.name = c1.name
AND c2.email = c1.email
AND c2.comment = c1.comment
)
AND c1.id <> (
SELECT MIN(c2.id)
FROM comments c2
WHERE c2.name = c1.name
AND c2.email = c1.email
AND c2.comment = c1.comment
)