MYSQL从每个类别中选择一个随机记录

此查询以随机顺序返回加入类别的所有项目：

SELECtc.id AS cid, c.category, i.id AS iid, i.nameFROM categories cINNER JOIN items i ON c.id = i.categoryORDER BY RAND()

要将每个类别限制为一个类别，请将查询包装在 partial中

GROUP BY

SELECt * FROM (    SELECt    c.id AS cid, c.category, i.id AS iid, i.name    FROM categories c    INNER JOIN items i ON c.id = i.category    ORDER BY RAND()) AS shuffled_itemsGROUP BY cid

请注意，当查询同时具有

GROUP BY

ORDERBY

我了解此查询不会赢得任何比赛。我愿意提出建议。