附近的人計算方法-----使用mysql指令碼計算方法

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附近的人計算方法drop  function if exists getDistance;DELIMITER $$  CREATE DEFINER=`root`@`localhost` FUNCTION `getDistance`(     lon1 float(10,7)     ,lat1 float(10,7)    ,lon2 float(10,7)     ,lat2 float(10,7)) RETURNS doublebegin    declare d double;    declare radius int;    set radius = 6378140; #假設地球為正球形，直徑為6378140米    set d = (2*ATAN2(SQRT(SIN((lat1-lat2)*PI()/180/2)           *SIN((lat1-lat2)*PI()/180/2)+           COS(lat2*PI()/180)*COS(lat1*PI()/180)           *SIN((lon1-lon2)*PI()/180/2)           *SIN((lon1-lon2)*PI()/180/2)),           SQRT(1-SIN((lat1-lat2)*PI()/180/2)           *SIN((lat1-lat2)*PI()/180/2)           +COS(lat2*PI()/180)*COS(lat1*PI()/180)           *SIN((lon1-lon2)*PI()/180/2)           *SIN((lon1-lon2)*PI()/180/2))))*radius;    return d;end$$DELIMITER ; select getDistance(116.3899,39.91578,116.3904,39.91576);