MySQL 联合多表统计查询

SELECT m.user_id, b_total, c_total, d_total FROM a m, (SELECT user_id, COUNT(*) b_total FROM b GROUP BY user_id) n,

(SELECT user_id, COUNT(*) c_total FROM c GROUP BY user_id) j, (SELECT user_id, COUNT(*) d_total FROM d GROUP BY user_id) k,

WHERE m.user_id = n.user_id AND m.user_id = j.user_id AND m.user_id = k.user_id

in后边的sql有问题。

你试试单独运行“select pid from repost group by pid order by count(pid) desc limit 0, 3”。估计会保错。

查出A表中 id ， 其对应B表中字母为A,C

select id from A where id in (select id from B where 字母 in ('A','C'))

单查B表

select id from B where 字母 in ('A','C')

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