如何在声明变量时从日期时间值中过滤掉一天(日期部分)

Question

DECLARE     @LatestFlightDate DATETIME, @LFDay INT
SET  @LatestFlightDate = (
              SELECT        MAX(FlightDateTime)
          FROM              dbo.Flight
                        )

SET   @LFDay = (    
    SELECT  DATEPART(DD, @LatestFlightDate)
    FROM    dbo.Flight
    )   
         )  

Answer 1

DECLARE @LatestFlightDate DATETIME, @LFDay INT
SELECT @LatestFlightDate = MAX(FlightDateTime) FROM dbo.Flight
SELECT @LFDay =  DATEPART(DD, @LatestFlightDate) FROM dbo.Flight 

Answer 2

你可以

简单地使用它DATEPART

DECLARE @LFDay INT = (SELECT DATEPART(DAY,MAX(FlightDateTime)) FROM dbo.Flight)

或

DECLARE @LFDay INT = (SELECT DAY(MAX(FlightDateTime)) FROM dbo.Flight)