Querying MySQL for latitude and longitude coordinates that are within a given mile radius

Question

I currently have a MySQL table that is structured as follows:

id         name     lon            lat  
-----      -----    -----------    -----------
1                   


        

Answer 1

Spherical Law of Cosines Formula
(37 and -122 are the latitude and longitude of your radius center)

SELECT id, ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) ) 
    * cos( radians( long ) - radians(-122) ) + sin( radians(37) ) * sin(radians(lat)) ) ) AS distance 
FROM myTable
HAVING distance < 50
ORDER BY distance 

Features

• Fastest
• Precision similar to Harvesine Formula

Haversine Formula

SELECT id, 3956 * 2 * ASIN(SQRT(POWER(SIN((37 - abs(lat)) * pi()/180 / 2), 2)
       + COS(37 * pi()/180 ) * COS(abs(lat) * pi()/180)
       * POWER(SIN((-122 - long) * pi()/180 / 2), 2) )) as  distance
FROM myTable
HAVING distance < 50
ORDER BY distance

Features

• Fast
• More robust to floating point errors

Note that 3959 is the Earth radius in miles. Earth radius in km: 6371

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