Get all objects provided there are other objects within the radius of each object?

Question

SQL

There is a table with records of objects. Columns id,name,lat(float),lon(float). How to get all objects provided there are other objects within the radius of each object. I understand that you first need to simply measure the distance between all objects and then filter out everything that does not fall under the condition through the HAVING construction. How to write sql query correctly?

Answer 1

SQL Geometry find all points in a radius .