SQL Server days in the current month

  select  getdate () -- current date 17:01:34. 717  select   month  (getdate ()) --  select   day  (getdate () of the current month ()) -- the current day of the month is 17  select  getdate () - day  (getdate () -- last day of last month 17:01:47. 920  select  dateadd (mm, 1, getdate ()) - day  (getdate () -- the last day of the month, 17:02:00. 437  select   day  (dateadd (mm, 1, getdate ()) - day  (getdate ()-31 days in this month