DECLARE @Method AS NVARCHAR
SET  @Method = 'DDD_t_s_2222_2222_01_2222'

DECLARE @number_of_years AS NVARCHAR


if @Method LIKE 'DDD_____%' begin

	SET @number_of_years = (@yearto-@yearfrom)+1 

end
else if @Method LIKE 'DDD_t%' begin

	if (SELECT SUBSTRING(@Method, 21, 1)) = 0 begin
		
		SET @number_of_years = (SELECT SUBSTRING(@Method, 22, 1))  	end
	else begin
		
		SET @number_of_years = (SELECT SUBSTRING(@Method, 21, 2))
	end
end