我有以下表格:
posts
post_id | user_id | text
1 | 12 | blabla
2 | 64 | sususus
和
comments
comment_id | post_id | user_id | text
1 | 1 | 55 | I like this...
2 | 2 | 66 | Yeah, me also!
...
现在帖子和评论通过 post_id id 连接起来。如何获得所有评论少于 18 条的帖子?