SELECT
id, (
3959 * acos (
cos ( radians(60.0000) )
* cos( radians( lat ) )
* cos( radians( lng ) - radians(30.0000) )
+ sin ( radians(60.0000) )
* sin( radians( lat ) )
)
) AS distance
FROM markers
HAVING distance < 30
ORDER BY distance
LIMIT 0 , 20;