"t="在 SELECT t = DATEADD(小时、n-1、@start) 中做什么，从 x 顺序 BY t;

Question

我发现这篇文章对我的时间范围有很大的帮助:

DECLARE 
@start TIME(0) = '11:00 AM', 
@end   TIME(0) =  '2:00 PM';
WITH x(n) AS 
(
SELECT TOP (DATEDIFF(HOUR, @start, @end) + 1) 
rn = ROW_NUMBER() OVER (ORDER BY [object_id]) 
FROM sys.all_columns ORDER BY [object_id]
)
SELECT t = DATEADD(HOUR, n-1, @start) FROM x ORDER BY t;

但是我不知道't ='在这个select子句中是什么或做什么。对于'rn = '

也是一样那是什么?这有专业术语吗?我怎么使用它?

Answer 1

将别名设置为字段结果

SELECT OriginalColumnName as MyFavorityName
FROM MyTableName

等于

SELECT MyFavorityName = OriginalColumnName
FROM MyTableName