mysql - 删除 SELECT Mysql 结果中的重复项，如果任何列 1 = 列 2 那么它是重复项

Question

好吧，我有一个名为 posts 的表，我尝试删除重复项，条件是如果 post_id 之一等于 post_dat_id，并且仅当 post_data_id == post_id 的 post_type 为 2 时才删除它。

帖子结构

post_id || post_data_id || post_type || post_user_id
==================================
1 || NULL || 0 || 10210

2 || 1 || 2 || 201020 <-- it shouldn't show this one because it meets the condition that post_type == 2 && the post_data_id is equal to one of the post_id. EDIT: also notice how this id = 2 but the post_data_id = 1. It is impossible for a row ot have the same post_id & post_data_id

2 || 1 || 0 || 202020

3 || 6 || 2 || 202020

我的mysql:

 SELECT p.*
 FROM posts p
 LEFT JOIN following f ON f.user_id =1
 AND p.post_user_id = f.follower_id 
 WHERE post_user_id =1
 OR f.user_id IS NOT NULL 
 ORDER BY  `p`.`post_time` DESC 
 LIMIT 0 , 10

编辑:我不想删除代码，我想做的只是在满足我选择的条件时不显示结果。另外，我已经在使用左连接，因为我的 sql 代码需要检查下表来获取用户 ID

编辑2:我还将post_data更改为post_data_id，因此它现在是纯int

Answer 1

还没有测试过这段代码，但我会做这样的事情:

select from posts p where p.id not in
(select q.id from posts q
where q.post_data = q.post_id and q.post_type = 2);