我想从mysql数据库中获取具有过滤器的行和near距离

Question

I want to fetch rows from MySql database with filter by near by and the limit of distance. I have created a query that is working fine for fetching the data near by, but I want to add a condition for distance limitation, that means If I want rows which have location of 20 km distance. This is the query that is working for near by.

$lat="";
$lon="";
$sql="SELECT *, 
  111.111 *
    DEGREES(ACOS(COS(RADIANS(".$lat."))
         * COS(RADIANS(Lat))
         * COS(RADIANS(".$lon." - Lon))
         + SIN(RADIANS(".$lat."))
         * SIN(RADIANS(Lat)))) AS d
FROM Table
ORDER BY d"

Answer 1

You can use HAVING Clause to achieve this

$sql="SELECT *, 
  111.111 *
    DEGREES(ACOS(COS(RADIANS(".$lat."))
         * COS(RADIANS(Lat))
         * COS(RADIANS(".$lon." - Lon))
         + SIN(RADIANS(".$lat."))
         * SIN(RADIANS(Lat)))) AS d
FROM Table HAVING d <= 20
ORDER BY d"