如何在SQL Server中获取一周的总条目数

Question

我有一个datetime列，即signed_in列，我需要每隔一周获取数据库中条目的总数，但是下面的代码返回0。请帮助我实现这一点。

SELECT COUNT(*) AS _total 
FROM FirstTimer 
WHERE MONTH(Signed_in) = DATEPART(WEEK,getdate());

图像链接是sql查询的结果，但是我如何仅获取_total列

Answer 1

您似乎想要：

SELECT DATEPART(WEEK, Signed_in) , COUNT(*) AS _total 
FROM FirstTimer
WHERE DATEPART(WEEK, signed_in) = DATEPART(WEEK, GETDATE())
GROUP BY DATEPART(WEEK, Signed_in); 

编辑：如果只需要_total，则可以：

SELECT COUNT(*) AS [_total] 
FROM FirstTimer
WHERE DATEPART(WEEK, signed_in) = DATEPART(WEEK, GETDATE());

Answer 2

您可以过滤大于一周中第一天的记录，而不是比较星期数。因为如果您比较周数，还需要比较年份。

SET DATEFIRST 1 

SELECT COUNT(*) AS _total 
FROM FirstTimer 
WHERE 
 Signed_in > SELECT CAST( DATEADD( DAY, 1 - DATEPART(WEEKDAY,GETDATE()) ,GETDATE()) AS DATE )