CREATE FUNCTION [dbo].[fnGetDistance]
(@LngBegin REAL, @LatBegin REAL, @LngEnd REAL, @LatEnd REAL)
RETURNS FLOAT
AS
BEGIN
--距离(千米)
DECLARE @Distance REAL
DECLARE @EARTH_RADIUS REAL
SET @EARTH_RADIUS = 6378.137
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
RETURN @Distance
END
