guys not a supabase related question, but... somebody of u have a postgres function to calc distance (km) betweend 2 coordinates?

Make sure the PostGIS extensions are enabled, and then the results on Google will work, for example: https://postgis.net/docs/ST_Distance.html https://stackoverflow.com/questions/24624257/postgis-distance-calculation

I want run a query where the coordinates are below or equal 300km

That's an entirely different question to the one you originally asked, and I'd suggest Googling for answers

I recently worked on postgis and collected some notes here https://notes.fyndx.io/Computer+Science/Programming/Database/Postgres/PostGis

sorry sometimes my english s*ck xD