-- =============================================

-- Author:Forrest

-- Create date: 2013-07-16

-- Description:    根据经纬度计算两点间的距离;返回米(m)

-- =============================================

ALTER FUNCTION [dbo].[Fun_MathRange]

(

    @in_Lat1 decimal(18,6),

    @in_Lng1 decimal(18,6),

    @in_Lat2 decimal(18,6),

    @in_Lng2 decimal(18,6)

)

RETURNS int

AS

BEGIN

    set @in_Lat1 = @in_Lat1 * PI() / 180.0;

    set @in_Lat2 = @in_Lat2 * PI() / 180.0;

    set @in_Lng1 = @in_Lng1 * PI() / 180.0;

    set @in_Lng2 = @in_Lng2 * PI() / 180.0;

    declare @a decimal(18,6),@b decimal(18,6),@c decimal(18,6)

    set @a = @in_Lat1 - @in_Lat2;

    set @b = @in_Lng1 - @in_Lng2;

    set @c = 2 * Asin(Sqrt(Power(Sin(@a/2),2) + Cos(@in_Lat1)*Cos(@in_Lat2)*Power(Sin(@b/2),2)))

    set @c = @c * 6378.137 --地球半径，单位：千米

    set @c = Round(@c * 10000,3) / 10000

    set @c = @c*1000

    return @c

END