Function to Retrieve only character part from the given string in SQL Server

Create FUNCTION RetrieveChar(@Val VARCHAR(1000))

RETURNS VARCHAR(100)
AS
BEGIN
DECLARE @Count INT
DECLARE @IntNum VARCHAR(100)
SET @Count = 0
SET @IntNum = ''
WHILE @Count <= LEN(@Val)
BEGIN
IF SUBSTRING(@Val,@Count,1) <> '0' AND SUBSTRING(@Val,@Count,1) <> '1'
AND SUBSTRING(@Val,@Count,1) <> '2' AND SUBSTRING(@Val,@Count,1) <> '3'
AND SUBSTRING(@Val,@Count,1) <> '4'AND SUBSTRING(@Val,@Count,1) <> '5'
AND SUBSTRING(@Val,@Count,1) <> '6' AND SUBSTRING(@Val,@Count,1) <> '7'
AND SUBSTRING(@Val,@Count,1) <> '8' AND SUBSTRING(@Val,@Count,1) <> '9'
BEGIN
SET @IntNum = @IntNum + SUBSTRING(@Val,@Count,1)
END
SET @Count = @Count + 1
END
RETURN @IntNum
END
GO

SELECT dbo.RetrieveChar('Amatya200Adi978tya');