Date Calulations

WEEK START DATE and WEEK END DATE

declare @dtDate as datetime

set @dtDate= getDate()

SET DATEFIRST 1

--WEEK START DATE

select convert(char(10),dateadd(week,-1,dateadd(day,-1*(datepart(weekday,@dtDate)-1),@dtDate)),101)

--WEEK END DATE

select convert(char(10),dateadd(day,-1*(datepart(weekday,@dtDate)-1),@dtDate),101)

MONTH START and END DATE

declare @dtDate as datetime

set @dtDate= getDate()

--MONTH START DATE

select convert(char(10),dateadd(month,-1,dateadd(day,-1*datepart(day,@dtDate)+1,@dtDate)),101)

--MONTH END DATE

select convert(char(10),dateadd(day,-1*datepart(day,@dtDate),@dtDate),101)

or
select DATEADD(MM, DATEDIFF(MM, 0, GETDATE()) + 1, 0)-1 AS MonthEndDate