alter function dbo.ToGregorianDate(@p as int =0)       
returns date as    
begin
	declare @res as date;

	declare @PersianDate nvarchar(7) = RIGHT (@p, 7) 

	DECLARE @Year INT = SUBSTRING(@PersianDate, 1, 3)
	DECLARE @Month INT = SUBSTRING(@PersianDate, 4, 2)
	DECLARE @Day INT = SUBSTRING(@PersianDate, 6, 2)

	DECLARE @DiffYear INT = @Year - 350

	DECLARE @Days INT = @DiffYear * 365.24 + CASE WHEN @Month < 7 THEN (@Month - 1) * 31 ELSE 186 + (@Month - 7) * 30 END + @Day

	DECLARE @StartDate DATETIME = '03/21/1971'
	set @res = @StartDate + @Days
	return CONVERT(DATE, @res);
end