我怎样才能获得每周的行数？

Question

我从表中选择：

SELECT DATEPART(WEEK, DayTime) as WeekNumber FROM dbo.Transactions

结果：

WeekNumber
1
1
1
2
2
3
4
4
5
4
5
3

如何计算每周的行数？

我需要这样的东西：

WeekNumber    CountOfRows
1             3
2             2
3             2
4             3
5             1

Answer 1

您需要GROUP BY周编号并使用COUNT功能

SELECT DATEPART(WEEK, DayTime), COUNT(*) 
FROM dbo.Transactions
GROUP BY DATEPART(WEEK, DayTime)

Answer 2

SELECT DATEPART(WEEK, DayTime) as WeekNumber, COUNT(1) as CountOfRows  
FROM dbo.Transactions 
GROUP BY WeekNumber;