php - Mysql Query-每个日期最多 3 个数据

Question

这些是我的数据库表数据，{我只维护了一个表}

我需要从每个 start_date 获取最多 3 个数据，

给我任何开发查询的想法，

Answer 1

SELECT a.*
FROM Table1 a
INNER JOIN Table1 b ON a.start_date = b.start_date AND a.event_id <= b.event_id
GROUP BY a.event_id,a.start_date
HAVING COUNT(*) <= 3
ORDER BY a.start_date 

Answer 2

我可能会建议你这个查询 -

SELECT * FROM (
  SELECT t1.*, COUNT(*) pos FROM table t1
    LEFT JOIN table t2
      ON t2.start_date = t1.start_date AND t2.event_id <= t1.event_id
  GROUP BY
    t1.start_date AND t1.event_id
  ) t
WHERE
  pos <= 3;

它在一个组中选择 3 行，其中 minevent_id为一start_date组。