To Calculate Distance with given Latitude and longitude using Sqlserver

CREATE FUNCTION dms2rad (@deg int, @min int, @sec float)
RETURNS float
AS
BEGIN
RETURN RADIANS(CONVERT(float, @deg) + CONVERT(float, @min)/60.0 + @sec/3600.0)
END





ALTER FUNCTION DistLatLong (@lat1 float, @lon1 float, @lat2 float, @lon2 float)
RETURNS float
AS
BEGIN
-- Parameters in RADIANS, result in statute miles
DECLARE @dlon float, @dlat float, @a float, @c float
SET @dlon = @lon2 - @lon1 SET @dlat = @lat2 - @lat1
SET @a = POWER(SIN(@dlat / 2.0), 2.0) +
COS(@lat1) * COS(@lat2) * POWER(SIN(@dlon / 2.0), 2.0)
SET @c = 2.0 * ATN2(SQRT(@a), SQRT(1.0 - @a))
RETURN round( 3956.0 * @c * 1.6,1)
END

-------------Or----------

ALTER FUNCTION [dbo].[DistanceBetween] (@Lat1 as real,
@Long1 as real, @Lat2 as real, @Long2 as real)
RETURNS real
AS
BEGIN
DECLARE @dLat1InRad as float(53);
SET @dLat1InRad = @Lat1 * (PI()/180.0);
DECLARE @dLong1InRad as float(53);
SET @dLong1InRad = @Long1 * (PI()/180.0);
DECLARE @dLat2InRad as float(53);
SET @dLat2InRad = @Lat2 * (PI()/180.0);
DECLARE @dLong2InRad as float(53);
SET @dLong2InRad = @Long2 * (PI()/180.0);
DECLARE @dLongitude as float(53);
SET @dLongitude = @dLong2InRad - @dLong1InRad;
DECLARE @dLatitude as float(53);
SET @dLatitude = @dLat2InRad - @dLat1InRad;
/* Intermediate result a. */
DECLARE @a as float(53);
SET @a = SQUARE (SIN (@dLatitude / 2.0)) + COS (@dLat1InRad)
* COS (@dLat2InRad)
* SQUARE(SIN (@dLongitude / 2.0));
/* Intermediate result c (great circle distance in Radians). */
DECLARE @c as real;
SET @c = 2.0 * ATN2 (SQRT (@a), SQRT (1.0 - @a));
DECLARE @kEarthRadius as real;
/* SET kEarthRadius = 3956.0 miles */
SET @kEarthRadius = 6376.5; /* kms */
DECLARE @dDistance as real;
SET @dDistance = @kEarthRadius * @c;
return (@dDistance);
END