sql-server - 如何为 SUM 列指定名称？

Question

如何将列名分配给 SUM 列？

IE。

select OwnerUserId, SUM(PostScore)
INTO Experts
from ...

我收到此错误:

An object or column name is missing or empty. For SELECT INTO statements, verify each column has a name. For other statements, look for empty alias names. Aliases defined as "" or [] are not allowed. Change the alias to a valid name.

我猜是因为包含 SUM 结果的列没有名称。

Answer 1

首先没有 SQL-Server 2003。只有 2000、2005、2008(然后是 2008R2、2012 和最新的 2014)。

至于名字——叫别名——你可以用AS .这是标准的 SQL 语法:

SELECT OwnerUserId, SUM(PostScore) AS PostScoreSum
INTO Experts 
FROM ... 

但是AS是可选的，因此您也可以在没有它的情况下为列设置别名:

SELECT OwnerUserId, SUM(PostScore)  PostScoreSum
INTO Experts 
FROM ... 

您也可以使用(专有，仅在 SQL-Server 中)alias = column句法:

SELECT OwnerUserId, PostScoreSum = SUM(PostScore)  
INTO Experts 
FROM ...