hi, You can write a query like

select Case When Month(getdate()) <=3 Then '31-03-'+ Convert(Varchar(4),Year(GetDate()))

When Month(getdate()) > 3 AND Month(getdate()) <=6 THEN '31-06-' + Convert(Varchar(4),Year(GetDate()))

When Month(getdate()) > 9 AND Month(getdate()) <=9 THEN '31-09-' + Convert(Varchar(4),Year(GetDate()))

ELSE '31-12-' + Convert(Varchar(4),Year(GetDate())) END

this will return you the expected result