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--FUNCTION  Name：udf_WeekDayName

--作者：数据库之家

--FUNCTION ：SQL SERVER获取星期

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CREATE FUNCTION [dbo].[udf_WeekDayName]

(    
)
RETURNS @WeekDayName TABLE([Id] INT,[WeekDayName] NVARCHAR(15))
AS
BEGIN    
    INSERT INTO @WeekDayName ([Id],[WeekDayName]) VALUES (0,'Saturday'),(1,'Sunday'),(2,'Monday'),(3,'Tuesday'),(4,'Wednesday'),(5,'Thursday'),(6,'Friday')
    RETURN
END

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CREATE FUNCTION [dbo].[udf_WeekDayNameOfDate]
(
  @Date DATETIME
)
RETURNS NVARCHAR(10)
BEGIN
RETURN
    CASE (DATEPART(dw, @Date) + @@DATEFIRST) % 7
    WHEN 0 THEN 'Saturday'
    WHEN 1 THEN 'Sunday'
    WHEN 2 THEN 'Monday'
    WHEN 3 THEN 'Tuesday'
    WHEN 4 THEN 'Wednesday'
    WHEN 5 THEN 'Thursday'
    WHEN 6 THEN 'Friday'    
  END
END