在两列之间选择最新日期 [英] Selecting most recent date between two columns

问题描述

如果我有一个表（除其他列外）有两个DATETIME列，我该如何从这两列中选择最近日期。

If I have a table that (among other columns) has two DATETIME columns, how would I select the most recent date from those two columns.

示例：

ID     Date1     Date2

1      1/1/2008   2/1/2008

2      2/1/2008   1/1/2008

3      1/10/2008  1/10/2008

如果我希望我的结果看起来像

If I wanted my results to look like

ID     MostRecentDate

1      2/1/2008

2      2/1/2008

3      1/10/2008

是否有一种简单的方法可以使我明显地忽略掉？我知道我可以执行子查询和case语句，甚至可以在sql server中编写一个函数来处理它，但是我脑子里已经有了一个内置的max-compare类型函数，我只是忘记了。

Is there a simple way of doing this that I am obviously overlooking? I know I can do subqueries and case statements or even write a function in sql server to handle it, but I had it in my head that there was a max-compare type function already built in that I am just forgetting about.

推荐答案

案例是恕我直言，您最好的选择：

CASE is IMHO your best option:

SELECT ID,
       CASE WHEN Date1 > Date2 THEN Date1
            ELSE Date2
       END AS MostRecentDate
FROM Table

---

如果其中一列为空，则只需将其包含在 COALESCE ：

.. COALESCE(Date1, '1/1/1973') > COALESCE(Date2, '1/1/1973')

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