ALTER FUNCTION dbo.HexToDecimal 
	(
	@HexValue varchar(18)
	)
RETURNS BIGINT
AS
BEGIN
	DECLARE @DigitPlace AS INT
	DECLARE @DecimalValue AS BIGINT
	DECLARE @PlaceValue as BIGINT
	DECLARE @PlaceAscii as BIGINT
	DECLARE @HexDigit as CHAR(1)
	
	SET @HexValue = UPPER(@HexValue)

	IF SUBSTRING(@HexValue,1,2) = '0X'
	BEGIN
		SET @HexValue = SUBSTRING(@HexValue,3, LEN(@HexValue) - 2)
	END
	
	SET @DigitPlace = 0
	SET @DecimalValue = 0
	WHILE @DigitPlace < LEN(@HexValue)
	BEGIN
		SET @HexDigit = SUBSTRING(@HexValue, LEN(@HexValue) - @DigitPlace, 1)
		SET @PlaceAscii = ASCII(@HexDigit)
		IF @PlaceAscii > 64
		BEGIN
			SET @PlaceValue = (@PlaceAscii - 55) 
		END
		ELSE
		BEGIN
			SET @PlaceValue = (@PlaceAscii - 48) 
		END
		IF @DigitPlace = 0
		BEGIN
			SET @DecimalValue = @PlaceValue
		END
		ELSE
		BEGIN
			SET @DecimalValue = @DecimalValue + (@PlaceValue * POWER(16, @DigitPlace))
		END
		SET @DigitPlace = @DigitPlace + 1
	END

	RETURN  @DecimalValue
END