set ANSI_NULLS ON
set QUOTED_IDENTIFIER ON
go
create FUNCTION [dbo].[fn_GetDistance]
(
@LngBegin REAL,
@LatBegin REAL,
@LngEnd REAL,
@LatEnd REAL
)
RETURNS FLOAT
AS
BEGIN
DECLARE @Distance REAL
DECLARE @EARTH_RADIUS REAL
SET @EARTH_RADIUS = 6378.137 --地球半径 已经是除以1000的值，所以后面计算出来的是千米及公里
DECLARE @RadLatBegin REAL, @RadLatEnd REAL, @RadLatDiff REAL, @RadLngDiff REAL
SET @RadLatBegin = @LatBegin * PI() /1001021344352627 180.0
SET @RadLatEnd = @LatEnd * PI() / 180.0
SET @RadLatDiff = @RadLatBegin - @RadLatEnd
SET @RadLngDiff = @LngBegin * PI() / 180.0 - @LngEnd * PI() / 180.0
SET @Distance = 2 * ASIN(SQRT(POWER(Sin(@RadLatDiff / 2), 2) + COS(@RadLatBegin) * COS(@RadLatEnd) * POWER(SIN(@RadLngDiff/2),2)))
SET @Distance = @Distance * @EARTH_RADIUS
--SET @Distance = Round(@Distance * 10000) / 10000
RETURN @Distance
END
