TSQL: Dates

Date format requirement: YYYY-MM-DD

• Get today's date

          select cast(getdate() as date)  

• Get first day of the current month

          select cast(dateadd(dd, -DAY(getdate())+1, GETDATE()) as date)         
          select cast(left(cast(getdate() as date), 8) as varchar) + '01'

• Get last day of the current month 

          select cast(DATEADD(s,-1,DATEADD(mm, DATEDIFF(m,0,GETDATE())+1,0)) as DATE)

• Get first day of the previous month

          select cast(dateadd(dd,-(day(dateadd(m, -1, GETDATE()))-1),dateadd(m, -1, GETDATE())) as DATE)

• Get last day of the previous month

          select cast(DATEADD(dd,-(DAY(GETDATE())),GETDATE()) as date)