两点经纬度之间的距离计算---mysql版

函数名：fnGetdistance

函数体：

BEGIN

DECLARE Distance REAL DEFAULT 0;

DECLARE EARTH_RADIUS REAL DEFAULT 6378.137;

DECLARE RadLatBegin REAL DEFAULT 0;  

DECLARE RadLatEnd REAL DEFAULT 0;  

DECLARE RadLatDiff REAL DEFAULT 0;  

DECLARE RadLngDiff REAL DEFAULT 0;  

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 ROUND(Distance,1);

END