PHP从多个表中选择

Question

I have a article pages, that i only want to show feed of the users that every account is following, kinda like twitter. I have to distinct tables one is called posts other is called followers I want to loop the articles but i want it to select only the users that my account is following. I just need the SQL query that can do that since the PHP part of the rest i can perform it

Something like this , although i know that this one does not work

$connect->query("SELECT id,userid,postagem FROM posts WHERE IN (SELECT followed FROM followers WHERE whofollowed = '$userd' )  ORDER BY id DESC LIMIT 13");

Answer 1

假设followed者也是关注者表中的一个用户ID：

$connect->query("SELECT id,userid,postagem FROM posts WHERE userid IN (SELECT followed FROM followers WHERE whofollowed = '$userd' )  ORDER BY id DESC LIMIT 13")