select a.posts_id,a.forumid,count(b.comments_id) as commentsNum
from posts a left join comments b on a.posts_id=b.postsid
group by b.postsid having a.forumid=1
from posts a left join comments b on a.posts_id=b.postsid
group by b.postsid having a.forumid=1
解决方案 »
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