方式1：st_distance_sphere:沒(méi)用除以1000，所以是以米為單位
SELECT *,st_distance_sphere(point(lng,lat),point(116.3424590000,40.0497810000)) as distance FROM school ORDER BY distance?ASC
方式2：st_distance:st_distance 計(jì)算的結(jié)果單位是度，需要乘111195（地球半徑6371000*PI/180）是將值轉(zhuǎn)化為米。
SELECT *,(st_distance(point(lng,lat),point(116.3424590000,40.0497810000))*111195/1000 ) as distance?FROM school?ORDER BY distance?ASC
方式3:
select *,
ROUND(6378.138*2*ASIN(SQRT(POW(SIN(({$lat}*PI()/180-lat*PI()/180)/2),2)+COS({$lat}*PI()/180)*COS(lat*PI()/180)*POW(SIN(({$lng}*PI()/180-lng*PI()/180)/2),2)))*1000) AS distance?
from school?order by distance?asc
