If you have a problem that involves finding the things within X distance of other things or finding what things
have nothing within X distance
do not use
ST_Distance for filtering and also do not try to use
ST_Intersects + ST_Buffer.
ST_DWithin instead. Why?
ST_DWithincan use an index and
ST_Bufferis just an approximation of a buffer and not an exact buffer
Also note that
ST_DWithin is supported for both geometry and geography.