如何从周数和工作日获取日期

Question

我有这个数据集，WeekNo（年和周）- WeekDayName 是有数据的那一天。我需要知道具体日期。

WeekNo  WeekDayName
------  -----------
201905  Mandag
201905  Mandag
201905  Mandag
201905  Tirsdag
201905  Tirsdag
201905  Tirsdag
201905  Onsdag
201905  Onsdag
201905  Onsdag
201905  Torsdag
201905  Torsdag
201905  Torsdag
201905  Fredag
201905  Fredag
201905  Fredag

想要的结果：

WeekNo  WeekDayName Date
------  ----------- -----
201905  Mandag      2019-01-28
201905  Mandag      2019-01-28
201905  Mandag      2019-01-28
201905  Tirsdag     2019-01-29
201905  Tirsdag     2019-01-29
201905  Tirsdag     2019-01-29
201905  Onsdag      2019-01-30
201905  Onsdag      2019-01-30
201905  Onsdag      2019-01-30
201905  Torsdag     2019-01-31
201905  Torsdag     2019-01-31
201905  Torsdag     2019-01-31
201905  Fredag      2019-02-01
201905  Fredag      2019-02-01
201905  Fredag      2019-02-01

我试过了，但它只给了我一周的开始：

declare @IntWeek as varchar(20) SET @IntWeek = '201905'

SELECT DATEADD(wk, DATEDIFF(wk, @@DATEFIRST, LEFT(@IntWeek,4)+'-01-01') + (cast(RIGHT(@IntWeek,2) as int)-1), @@DATEFIRST) AS StartOfWeek

Answer 1

你可以考虑 Calendar Table

之后就可以轻松得到结果

select date 
from Auxiliary.Calendar 
where Year = CAST(LEFT(@IntWeek,4) as int)
  and Week = CAST(RIGHT(@IntWeek,2) as int)
  and WeekDay = 'Mondag'

Answer 2

创建一个接收 2 个参数的函数：

1.- your First day of the week

2.- the day name

The function must do IF

IF dayName = 'Sunday'
  Return same date
Else If dayName = 'Monday
  Return Data + 1 day

.....

如何从周数和工作日获取日期

How to get date from WeekNumber and WeekDay

tsql

sql-server

sql-server-2017