计数让它返回一个结果

Question

我正在开展一个项目，我需要让所有喜欢该帖子的用户及其用户名和其他信息。

我尝试创建一个像这样的连接查询

$sql = "SELECT U.id AS userid, U.name AS NAME, U.username AS username,
               U.verified AS verified, U.private AS private,
               COUNT(IFOLLOW.user_id) AS i_follow, 
               COUNT(FR.user_id) AS requested 
        FROM posts AS P 
        LEFT JOIN likes AS L ON L.post_id = :postid 
        LEFT JOIN users AS U ON U.id = L.user_id 
        LEFT JOIN followers AS IFOLLOW 
               ON IFOLLOW.user_id = :userid AND IFOLLOW.following_id = U.id 
        LEFT JOIN follow_requests AS FR 
               ON FR.requester = :userid AND FR.user_id = U.id WHERE P.id = :postid";

我使用COUNT()计算用户是否关注/请求关注正在查看喜欢列表的用户。如果它表示1则意味着如果0没有则它们跟随/请求它们。问题是，当我包含count方法时，它将返回它作为一个结果。当我不包括计数时它会返回多个，所以我可以通过它们运行foreach。

我做错了什么才能把它作为一个结果？

Answer 1

如果要聚合分区而不是整个表，则应添加GROUP BY子句。尝试添加

GROUP BY U.id, U.name, U.username, U.verified, U.private

在您的查询结束时。