Mysql 查询-每个日期最多 3 个数据

Question

these is my DB table data,{ i have maintained only one Table}

I need to fetch max 3 data from each start_date,

give me any idea to develop query,,

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

I may suggest you this query -

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;

It selects 3 rows with min event_id in a start_date group.