只保留字符串的中文

CREATE FUNCTION fu_getwords(@cc VARCHAR(100))
RETURNS VARCHAR(100)
AS
begin
DECLARE @n INT,@i INT,@clearstr VARCHAR(100),@gg VARCHAR(10)
SET @n=LEN(@cc)
SET @i=1
SET @clearstr=''
WHILE(@i<=@n)
BEGIN
SET @gg= SUBSTRING(@cc,@i,1)
IF(UNICODE(@gg) BETWEEN 19968 AND 40869)
SET @clearstr=@clearstr+@gg
SET @i=@i+1
END
RETURN @clearstr
end