PostGIS is a spatial database extender for PostgreSQL object-relational database. It adds support for geographic objects allowing location queries to be run in SQL.

> SELECT superhero.name FROM city, superhero WHERE ST_Contains(city.geom, superhero.geom) AND city.name = "Gotham";

In addition to basic location awareness, PostGIS offers many features rarely found in other competing spatial databases such as Oracle Locator/Spatial and SQL Server. Refer to PostGIS Feature List for more details.

http://postgis.net/docs/manual-2.2/