Question

我有一张桌子

**user_id** | **date**
1           | 2012-10-18 09:34:4
3           | 2012-10-18 09:34:54
5           | 2012-10-17 09:14:54
6           | 2012-10-17 09:13:24
4           | 2012-10-16 08:34:54
9           | 2012-10-16 08:34:54

我想要的是具有最新日期时间的user_id，即

**user_id** | **date**
3           | 2012-10-18 09:34:54
5           | 2012-10-17 09:14:54
4           | 2012-10-16 08:34:54

Answer 1

在GROUP BY列的日期部分使用date（似乎类型为DATETIME）：

SELECT user_id, MAX(date) FROM table GROUP BY DATE(date);

Answer 2

要让一位用户获得最新的日期时间，请尝试使用

SELECT user_id FROM TB_NAME ORDER BY date DESC LIMIT 0,1

Answer 3

如果您只需要一个用户

SELECT 
    MAX(date) as LatestDateTime
FROM 
    mytable

对于多个用户

SELECT 
    *
FROM 
    mytable
ORDER By date DESC

Answer 4

尝试：

SELECT user_id, max(date) from user group by user_id

或

select user_id from user where date = (select max(date) from user)

Answer 5

试试这个：

select * from (
   select user_id, date
   from mytable
   order by date desc ) x
group by date(date);

注意：这是一个仅限mysql的解决方案，但它有效！

Answer 6

另一个SQL Fiddle

select user_id, `date`
from mytable t1
join (select max(`date`) as max_date
      from mytable
      group by date(`date`)) t2 on t1.`date` = t2.max_date

Answer 7

只是一个猜测，我希望它有效。

    SELECT t.user_id, t.date
    FROM table t
    WHERE t.date = (SELECT MAX(t2.date) FROM table t2 GROUP BY t2.date HAVING t2.date = t.date)

古德勒克！

Sql查询以获取具有最新日期时间的用户标识

7 个答案: