MySQL多对多选择

关键是在GROUP BY / HAVINg中使用COUNT个DISTINCT电话名称。当计数为2时，您将知道用户同时拥有 两部 电话。

SELECt m5.name    FROM mark5 m5        INNER JOIN mark4 m4 ON m5.uid = m4.uid        INNER JOIN mark3 m3 ON m4.phoneid = m3.phoneid    WHERe m3.name in ('HTC', 'Samsung')    GROUP BY m5.name    HAVINg COUNT(DISTINCT m3.name) = 2;