In my previous post about geo-spatial search in
MySQL I described *(along with other things)* how to
use geo-distance functions. In this post I will describe the
geo-spatial distance functions in more details.

If you need to calculate an exact distance between 2 points on
Earth in MySQL *(very common for geo-enabled
applications)* you have at least 3 choices.

- Use stored function and implement haversine formula
- Use UDF (user defined function) for haversine (see below)
- In MySQL 5.6 you can use st_distance …