You can use ST_ClosestPoint() to find the closest one to each point. If you use that in combination with make line you should be able to achieve what you need. Here is a link to the documentation for ST_ClosestPoint().

You can use ST_ClosestPoint() to find the closest one to each point. If you use that in combination with make line you should be able to achieve what you need. Here is a link to the documentation for ST_ClosestPoint().

You could do it like this -

select st_asgeojson(st_makeline(g)) from 

    (select geometry as g from testing group by geometry order by st_closestpoint(geometry, geometry)) as f