sql 计算周围公里语句

$lng2 = set_post('lng'); //当前位置坐标
$lat2 = set_post('lat');

round((2*ATAN2(SQRT(SIN((`gps`.`gps_lat`-$lat2)*PI()/180/2)
        *SIN((`gps`.`gps_lat`-$lat2)*PI()/180/2)+
        COS($lat2*PI()/180)*COS(`gps`.`gps_lat`*PI()/180)
        *SIN((`gps`.`gps_lng`-$lng2)*PI()/180/2)
        *SIN((`gps`.`gps_lng`-$lng2)*PI()/180/2)),
        SQRT(1-SIN((`gps`.`gps_lat`-$lat2)*PI()/180/2)
        *SIN((`gps`.`gps_lat`-$lat2)*PI()/180/2)
        +COS($lat2*PI()/180)*COS(`gps`.`gps_lat`*PI()/180)
        *SIN((`gps`.`gps_lng`-$lng2)*PI()/180/2)
        *SIN((`gps`.`gps_lng`-$lng2)*PI()/180/2))))*6378140) < 200000  LIMIT 6