CREATE FUNCTION getDistance(lng1 DOUBLE,lat1 DOUBLE,lng2 DOUBLE,lat2 DOUBLE) RETURNS DOUBLE
BEGIN
DECLARE lat1_ double;
DECLARE lat2_ double;
DECLARE lng1_ double;
DECLARE lng2_ double;
DECLARE distance double;
DECLARE R INT;
set R=6371;
set lat1_ = (PI()/ 180) * lat1;
set lat2_ = (PI() / 180) * lat2;
set lng1_ = (PI() / 180) * lng1;
set lng2_ = (PI() / 180) * lng2;
set distance=ACOS(SIN(lat1_)*SIN(lat2_)+COS(lat1_)*COS(lat2_)*COS(lng2_-lng1_))*R*1000;
RETURN distance;
end