以周一为每周的第一天，计算周数

#mssql

CREATE FUNCTION [dbo].[fn_GetWeekDay] 
(
    @InputDate            Date,
    -- @FirstDayOfWeek取值为1到7，若为1，表明周一是一周的第一天，若为7，表明周日是一周的第一天。
    @FirstDayOfWeek        int = 1
)
RETURNS int
AS
BEGIN
    RETURN DATEPART(DW,DATEADD(d,@@DATEFIRST-@FirstDayOfWeek,@InputDate))
END

CREATE FUNCTION [dbo].[fn_GetWeekNumber] 
(
    @InputDate            Date,
    -- @FirstDayOfWeek取值为1到7，若为1，表明周一是一周的第一天，若为7，表明周日是一周的第一天。
    @FirstDayOfWeek        int = 1
)
RETURNS int
AS
BEGIN
    DECLARE @WeekDayOfNewYearDay int
    SET @WeekDayOfNewYearDay = [dbo].fn_GetWeekDay(DATENAME(Year,@InputDate)+'-01-01',@FirstDayOfWeek)
    
    RETURN CEILING((DATEPART(DY,@InputDate)-(@FirstDayOfWeek-@WeekDayOfNewYearDay+1))/7)+1
END
#mysql

#1为周一为第一天
select YEARWEEK(DATE_SUB( curdate(),INTERVAL 1 day ) ,1)

#0为周日为第一天
select YEARWEEK(DATE_SUB( curdate(),INTERVAL 1 day ) )