SELECT
      pe.path,
      pe.cmdline,
      pe.cwd,
      pe.gid,
      pe.egid,
      pe.uid,
      pe.euid,
      pe.pid,
      pe.parent,
      pe.time,
      (select coalesce((SELECT cmdline FROM process_events AS parent_cmdline0 WHERE pid=pe.parent), (SELECT cmdline FROM processes AS parent_cmdline1 WHERE pid=pe.parent))) AS parent_cmdline
    FROM
      process_events AS pe;

with raw as (select
pid,
parent,
path
from processes)
select
  p.pid,
  p.parent,
  p.path as cpath,
 pp.path as ppath
from raw as p
left join raw as pp ON p.parent = pp.pid
;