بررسی اطلاعات کد ملی در SQL Server

در ذیل کد در اختیار شما قرار گرفته است :

CREATE FUNCTION dbo.Fnc_CheckCodeMelli	(@CodeMelli VARCHAR(10))
RETURNS VARCHAR(100)
AS
BEGIN
DECLARE @ErrorMessage VARCHAR(100)
	,@C INT
	,@N INT
	,@R INT
SET @ErrorMessage = ''
IF (
	LEN(@CodeMelli) <> 10
	OR @CodeMelli = '0000000000'
	OR @CodeMelli = '1111111111'
	OR @CodeMelli = '2222222222'
	OR @CodeMelli = '3333333333'
	OR @CodeMelli = '4444444444'
	OR @CodeMelli = '5555555555'
	OR @CodeMelli = '6666666666'
	OR @CodeMelli = '7777777777'
	OR @CodeMelli = '8888888888'
	OR @CodeMelli = '9999999999'
	)
BEGIN
	SET @ErrorMessage = 'کد ملی نامعتبر است'
END
ELSE
BEGIN
	SET @C = cast(SUBSTRING(@CodeMelli, 10, 1) as int)
	SET @N = (cast(SUBSTRING(@CodeMelli, 1, 1) as int) * 10) +
		(cast(SUBSTRING(@CodeMelli, 2, 1) as int) * 9) +
		(cast(SUBSTRING(@CodeMelli, 3, 1) as int) * 8) +
		(cast(SUBSTRING(@CodeMelli, 4, 1) as int) * 7) +
		(cast(SUBSTRING(@CodeMelli, 5, 1) as int) * 6) +
		(cast(SUBSTRING(@CodeMelli, 6, 1) as int) * 5) +
		(cast(SUBSTRING(@CodeMelli, 7, 1) as int) * 4) +
		(cast(SUBSTRING(@CodeMelli, 8, 1) as int) * 3) +
		(cast(SUBSTRING(@CodeMelli, 9, 1) as int) * 2)
	SET @R = @N % 11
	IF ((@R = 0 AND @R = @C) OR (@R = 1 AND @C = 1) OR (@R > 1 AND @C = 11 - @R))
		SET @ErrorMessage = 'کد ملی معتبر است'
	ELSE
		SET @ErrorMessage = 'کد ملی نامعتبر است'
END
RETURN @ErrorMessage
END
GO