sql server2008根据经纬度计算两点之间的距离

--通过经纬度计算两点之间的距离
create  FUNCTION [dbo].[fnGetDistanceNew]

--LatBegin 开始经度
--LngBegin 开始维度
--29.490295,106.486654,29.615467, 106.581515

(@LatBegin1 varchar(128), @LngBegin1 varchar(128),@location varchar(128))
Returns real
AS
BEGIN
--转换location字段,防止字段太长.影响SQL美观
declare  @LatBegin REAL
declare  @LngBegin REAL
declare  @LatEnd REAL
declare  @LngEnd REAL
set @LatBegin=Convert(real,@LatBegin1)
set @LngBegin=Convert(real,@LngBegin1)
set @LatEnd=Convert(real,SUBSTRING(@location,0,charindex('&',@location)))
set @LngEnd=Convert(real,SUBSTRING(@location,charindex('&',@location)+1,LEN(@location)))

--距离(千米)
DECLARE @Distance      REAL
DECLARE @EARTH_RADIUS  REAL
SET @EARTH_RADIUS = 6371.004

DECLARE @RadLatBegin  REAL,
@RadLatEnd    REAL,
@RadLatDiff   REAL,
@RadLngDiff   REAL

SET @RadLatBegin = @LatBegin *PI()/ 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) / 10000,5)
RETURN @Distance

END