Question

这是我的表

+---------------------+
| access_time         |
+---------------------+
| 2014-02-17 12:00:00 |
| 2014-02-15 12:00:00 |
| 2014-02-15 12:00:00 |
| 2014-02-15 12:00:00 |
| 2014-02-15 11:00:00 |
| 2014-02-14 02:00:00 |
| 2014-02-13 18:00:00 |
| 2014-02-13 12:50:05 |
| 2014-02-13 12:48:57 |
| 2014-02-13 11:57:24 |
+---------------------+

我希望有这样的输出：

+---------------------+
| access_time         |
+---------------------+
| 2014-02-17 12:00:00 |
| 2014-02-15 12:00:00 |
| 2014-02-14 02:00:00 |
| 2014-02-13 18:00:00 |
+---------------------+

具有那种输出的SQL命令是什么？

Answer 1

如果你想每天任意一个时间，你可以这样做：

select access_time
from table t
group by date(access_time);

更典型的是，您可以选择您想要的次数，并执行以下操作：

select min(access_time)
from table t
group by date(access_time);

Answer 2

对于SQL Server 2008或更新版本，我建议：

select cast(access_time as date)
from t
group by cast(access_time as date)

Answer 3

我认为这应该有用

With cte as (Select *,row_number ()over(partion by convert(date,access_time) 
             order by access_time desc) rn from <yourtable>)
Select * from <yourtable> where rn=1

Answer 4

试试这个

从tablename group by date
中选择distinct cast（access_time as Date）

如何选择不同的日期，不包括当天的时间

4 个答案: