I tried the following select:
SELECT (id,name) FROM v_groups vg inner join people2v_groups p2vg on vg.id = p2vg.v_group_id where p2vg.people_id =0;
SELECT vg.id, vg.name FROM v_groups vg INNER JOIN people2v_groups p2vg ON vg.id = p2vg.v_group_id WHERE p2vg.people_id = 0;