将子查询与元素列表进行比较

Question

我想选择与标记ID列表匹配的所有帖子。我尝试了以下方法：

SELECT * FROM posts as t WHERE (SELECT tag_id FROM post_tags WHERE post_tags.post_id = t.id) = ALL (8, 1)

这会出现以下错误：

Uncaught PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '8, 1))'

如果有人知道如何解决这个问题，我会很高兴。

Answer 1

SELECT p.*  
  FROM posts p
  JOIN post_tags pt 
    ON pt.post_id = p.id 
 WHERE tag_id IN(1,8) 
 GROUP 
    BY p.id
HAVING COUNT(*) = 2 

（其中＆＃39; 2＆＃39;等于IN（）中的项目数。）