Thanks for ur reply.

I want current_week column before fifteen days from now.

That is, getdate() - 15 days = current_week. But this column is not in date data type

so I used query mentioned by you.. but its throwing error.

select case when dateadd(DATEPART(day, cast(Left(Ltrim(current_week), 10)as date)),-15,getdate()) then 'previous week' end

from mytable