SQL将两行合并到一个select语句中 [英] SQL Combine two rows into a select statement

问题描述

您好，



我有两列我正在运行一个独特的select语句。问题是我真的只想要第一列的一个独特的，第二个我想采取非NULL的一个或两个都是NULL然后传递NULL。



我正在使用这个选择语句。

Hello,

I have two columns that I am running a distinct select statement for. The problem is I really want just a distinct for the first column, the second one I would like to take the one that isn't NULL or if both are NULL then pass NULL.

I am using this select statement.

SELECT DISTINCT
           offer_id_new
           ,Date1
  FROM [PCGRecruitingDatabaseUpsize].[dbo].[ExtendOffer] 

它还给我这个

And it returns me this

offer_id_new    Date 
819    2009-05-08 00:00:00.000
864    NULL
864    2010-08-08 00:00:00.000
866    NULL

对于两个ID为864的ID，我想每个offer_id_new只拉一个，但这个ID864都有一个NULL日期和约会。如果存在，我想只有一行是日期。

For the two ID's of "864", I would like to pull only one per offer_id_new but this ID "864" has both a NULL date and a date. If this exists I would like to just have 1 row which is the date.

推荐答案

你也可以尝试聚合（分组）

You could also try an aggregate (group by)

SELECT      offer_id_new
           ,max(Date1)
  FROM [PCGRecruitingDatabaseUpsize].[dbo].[ExtendOffer]
GROUP BY offer_id_new

您好，



将'左连接'改为一个'内部联接'。



干杯

Hello,

Alter the 'left join' into a 'inner join'.

Cheers

我想通了。插入临时表，其中Date不为null。如果临时表中不存在id，则再次插入。

I figured it out. Insert into a temp table where Date is not null. Then insert again if the id does not exist in the temp table.

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