Haversine MSSQL

CREATE FUNCTION [dbo].[GetDistance]
(
      @lat1 Float(8),
      @long1 Float(8),
      @lat2 Float(8),
      @long2 Float(8)
)
RETURNS Float(8)
AS
BEGIN
 
      DECLARE @R Float(8);
      DECLARE @dLat Float(8);
      DECLARE @dLon Float(8);
      DECLARE @a Float(8);
      DECLARE @c Float(8);
      DECLARE @d Float(8);
 
      SET @R = 3960;
      SET @dLat = RADIANS(@lat2 – @lat1);
      SET @dLon = RADIANS(@long2 – @long1);
 
      SET @a = SIN(@dLat / 2) * SIN(@dLat / 2) + COS(RADIANS(@lat1))
                        * COS(RADIANS(@lat2)) * SIN(@dLon / 2) *SIN(@dLon / 2);
      SET @c = 2 * ASIN(MIN(SQRT(@a)));
      SET @d = @R * @c;
 
      RETURN @d;
 
END
GO