select
id_t,
u1.id_u as tester_id,
u1.username as tester_name,
u2.id_u as client_id,
u2.username as client_name,
name,
project_id_t,
activation_t,
date_add
from arr_project p
left join arr_tester t on t.project_id_t=p.id_p
left join arr_user u2 on u2.id_u=t.tester_id_t
, arr_user u1
where u1.id_u=p.client_id ORDER BY `id_t` DESC