Taking attribute from multiple points within fixed distance

Question

I have a list of point features each with a unique "ID". I need to run a fixed distance buffer on all 70,000 points to establish which points are within a fixed distance of each other than return the unique "ID"s for each point. These need to be within columns in the attributes table.

So point 1 (id-A) might have point 9 (id-x) and Point 87 (id-c) within 1 km. I need the attributes table of point 1 to list id-A, then id-x then id c, all in columns for export to Excel where I can concentrate them with comers in between.

Answer 1

You can generate such list using a virtual layer, no need for excel nor to have an undefined number of columns

go to the menu Layer > Add Layer > Add/Edit Virtual Layer... and enter the query

select a.id, a.geometry, group_concat(b.id) as near_ids, count(b.id) as near_count
from mylayer a 
 left join mylayer b 
   on PtDistWithin(a.geometry,b.geometry, 1000)
      and a.id <> b.id
group by a.id

Note that this query filters out itself (that is, point 1 is not consider as being near itself).
The distance is in the same unit as the projection.
By default, group_concat adds a coma between outputs.

Bonus: it also counts the number of nearby points for you!