SQL query to query nearby points of interest based on lat/long - SQLite

Question

Given a database that contains three fields:

Latitude Longitude Proximity

Where Lat and Long are GPS coordinates, and Proximity is (some unit - feet? Seconds? Mi

Answer 1

The Haversine formula is what you want. Using simple Euclidian distance formula isn't sufficient, because the curvature of the earth affects the distance between two points.

Creating a Store Locator with PHP, MySQL & Google Maps is an article about implementing this solution with MySQL, but SQLite doesn't support trig functions.

Check out the answers in Calculating Great-Circle Distance with SQLite here on Stack Overflow for further tips on extending SQLite functions so you can solve this.