使用多个表计入mysql

Question

我有两张桌子（MySQL）：

论坛：match_static_id，评论，......

匹配：static_id，.........

sql语句：

SELECT  forum.match_static_id, count(forum.comments) 'comments_no', matches.* 
from forum 
INNER JOIN matches ON forum.match_static_id = matches.static_id   
group by forum.match_static_id

我没有为每个匹配得到正确数量的评论（它总是将评论数量乘以4回复8的评论）甚至我使用group by。我的sql错了，我只想要你的线索吗？

Answer 1

您应该使用左连接而不是内部

SELECT forum.match_static_id, count(forum.comments) 'comments_no', matches.* from matches LEFT JOIN forum ON forum.match_static_id = matches.static_id
group by forum.match_static_id