mysql - Effectively selecting the closest (distance) record from a database

Question

I've got a database with a 40k venues and growing right now.

Assuming I'm the red dot

I want to be able to retrieve the closest record as quickly as possible.

However the distance too the next item could be anything. And there also might be 0-n matches. But do I need to load all 40000 results when I'm just looking for 1?

How can I sort the records by distance? Should it be done in MYSQL, or PHP? This calculation happens at almost every request, per user, per page, so the solution needs to be quick.

Edit Thanks for the quick and promising answers, I'll need to review these resources, and will accept/comment on answers within a few days.

Answer 1

this problem is covered in this Scribd presentation (theory + math formulas + Mysql): Geo Distance with MySQL

I hope it covers everything you need