mysql从每个组中选择2行

SELECt p.id, g.typeid, g.id, g.title
FROM products p
INNER JOIN (SELECt * FROM gallery a
WHERe (SELECt COUNT(*) FROM gallery b WHERe b.title = a.title AND b.id >= a.id) <= 2
) g ON p.id = g.typeid
WHERe p.id in (3,4,5)

编辑：

试试这个SQL小提琴演示

SELECt p.id, g.typeid, g.id, g.nameFROM products p INNER JOIN (SELECt * FROM gallery a WHERe (SELECt COUNT(*) FROM gallery b WHERe b.typeid = a.typeid AND b.id >= a.id) <= 2) g ON p.id = g.typeid WHERe p.id in (3,4,5) order by g.id asc

所以基本上这部分

WHERe (SELECt COUNT(*) FROM gallery b WHERe b.title = a.title AND b.id >= a.id) <= 2

用于替换

group by typeid