查詢test表按group_id分組取sort_id前100個
SELECT id AS '原數據ID',group_id AS '分組ID',sort_id AS '排序條件',num AS '排名'
FROM
(SELECT @row_number := CASE WHEN @customer_no = group_id THEN @row_number + 1 ELSE 1 END AS num /*如果同group_id那麼排名加1,否則更新爲1*/
,@customer_no := group_id AS group_id /*重新加載group_id*/
,id , sort_id /*原有數據*/
FROM test,( SELECT @customer_no := 0,@row_number := 0) AS t
ORDER BY group_id ,sort_id DESC ,id)a
WHERE num<=100