Question

这是我在数据库中的当前数据。

    ========================================
    id | IC      |date         |time       |
    1  | test    |2017-07-27   |14:19:26   |
    2  | test    |2017-07-27   |14:20:26   |
    3  | second  |2017-07-28   |06:58:55   |
    ========================================

我想获得每个IC的maxdate和maxtime。

我试过了：

SELECT id,pass_no,time_in,ic,date_in FROM `check_in` 
WHERE date_in = (SELECT MAX(date_in) FROM check_in) 
AND 
time_in = (SELECT MAX(time_in) FROM check_in) GROUP BY IC

但它只为我返回最后一行数据。我想要的结果就像

    ========================================
    id | IC      |date         |time       |
    2  | test    |2017-07-27   |14:20:26   |
    3  | second  |2017-07-28   |06:58:55   |
    ========================================

Answer 1

这将返回最大日期＆amp;每个时间：

select ic, max(date), max(time)
from check_in
group by ic

Answer 2

这应该有效

 select max(time),date,id 
 from (select max(date) as date,time,id from check-in group by time,id ) 
 group by date,id;

Answer 3

你可以使用元组和ic分组

  SELECT id,pass_no,time_in,ic,date_in 
  FROM `check_in` 
  WHERE (date_in, time_in, ic) in  (
        SELECT MAX(date_in), max(time_id), ic 
          FROM check_in
          GROUP BY id)

Answer 4

你试过＆＃34; OR＆＃34;条件反而＆＃34; AND＆＃34;？

从查询中选择最大日期和最长时间

4 个答案: