Ordering with SQL by nearest latitude & longitude coordinates (MySQL & SQLite)

nearby-coordinates.sql

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METHOD 1

This should roughly sort the items on distance in MySQL, and should work in SQLite.
If you need to sort them preciser, you could try using the Pythagorean theorem (a^2 + b^2 = c^2) to get the exact distance.
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SELECT *
FROM table
ORDER BY ((lat-$user_lat)*(lat-$user_lat)) + ((lng - $user_lng)*(lng - $user_lng)) ASC

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METHOD 2
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SELECT
    id, (
      6371 * acos (
      cos ( radians($user_lat) )
      * cos( radians( lat ) )
      * cos( radians( lng ) - radians($user_lng) )
      + sin ( radians($user_lat) )
      * sin( radians( lat ) )
    )
) AS distance
FROM table
HAVING distance < 30
ORDER BY distance
LIMIT 0 , 20;

SQLite doesn't have acos function so Method 2 only works on Mysql

SQLite doesn't have acos function

You can implement your own functions in SQLite. For example, math functions can [apparently] be added with extension-functions.c, downloadable from sqlite.org, or else a search of Stack Overflow has other options such as this one.

SQLite doesn't have acos function so Method 2 only works on Mysql

FYI: sqlite 3.35.0 has acos and many other functions. https://sqlite.org/releaselog/3_35_0.html

Thank you!!! You made my day xD

Thanks!