go
--創建經緯度距離計算函數
CREATEFUNCTION [dbo].[fnGetDistance]
--LatBegin 開始經度
--LngBegin 開始維度
(@LatBegin REAL, @LngBegin REAL, @LatEnd REAL, @LngEnd REAL)
RETURNSFLOAT
AS
BEGIN
--距離(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
--SET @Distance = Round(@Distance * 10000) / 10000

RETURN @Distance
END

@Distance的單位為:千米