计算2点间距离

单位米，算法来自百度http://api.map.baidu.com/library/GeoUtils/1.2/src/GeoUtils.js

CREATE FUNCTION [dbo].[ToDistance] 
(
    @Lng1 FLOAT,
    @Lat1 FLOAT,
    @Lng2 FLOAT,
    @Lat2 FLOAT
)
RETURNS FLOAT
AS
BEGIN
    -- Declare the return variable here
    DECLARE
        @Distance FLOAT

    SET @Lng1 = PI() * @Lng1 / 180
    SET @Lat1 = PI() * @Lat1 / 180
    SET @Lng2 = PI() * @Lng2 / 180
    SET @Lat2 = PI() * @Lat2 / 180

    -- Add the T-SQL statements to compute the return value here
    SET @Distance = 6370996.81 * ACOS((SIN(@Lat1) * SIN(@Lat2) + COS(@Lat1) * COS(@Lat2) * COS(@Lng2 - @Lng1))) / 1000

    -- Return the result of the function
    RETURN @Distance

END

 单位米，算法来自高德

CREATE FUNCTION [dbo].[ToDistance] 
(
	-- Add the parameters for the function here
	@Lng1 FLOAT,@Lat1 FLOAT,@Lng2 FLOAT,@Lat2 FLOAT
)
RETURNS FLOAT
AS
BEGIN
	-- Declare the return variable here
	DECLARE
		@Distance FLOAT,
		@Sin FLOAT,
		@SIN2 FLOAT,
		@SIN3 FLOAT,
		@SIN4 FLOAT

	SET @Lng1 = PI() * @Lng1 / 180
	SET @Lat1 = PI() * @Lat1 / 180
	SET @Lng2 = PI() * @Lng2 / 180
	SET @Lat2 = PI() * @Lat2 / 180

	SET @Sin = Sin(@Lng1);
    SET @Sin2 = Sin(@Lat1);
    SET @Sin3 = Sin(@Lng2);
    SET @Sin4 = Sin(@Lat2);

	SET @Lng1 = Cos(@Lng1);
    SET @Lat1 = Cos(@Lat1);
	SET @Lng2 = Cos(@Lng2);
	SET @Lat2 = Cos(@Lat2);

	-- Add the T-SQL statements to compute the return value here
    SET @Distance = Asin(Sqrt(((POWER((@Lng1 * @Lat1 - @Lng2 * @Lat2), 2)) + (POWER((@Lat1 * @Sin - @Lat2 * @Sin3), 2))) + (POWER((@Sin2 - @Sin4), 2))) / 2) * 1.27420015798544E7 / 1000

	-- Return the result of the function
	RETURN @Distance
END