select distinct b.name from custom_tests_results a
join students b
on a.student_id = b.student_id
join group_custom_tests c
on a.custom_test_id = c.id
where c.group_id = 69 and c.format = 'Пробные тесты ЕНТ'
and a.subject_id = 1
GROUP BY a.test_date, a.id, b.student_id, c.id

select distinct a.test_date from custom_tests_results a
join students b
on a.student_id = b.student_id
join group_custom_tests c
on a.custom_test_id = c.id
where c.group_id = 69 and c.format = 'Пробные тесты ЕНТ'
and a.subject_id = 1
GROUP BY a.test_date, a.id, b.student_id, c.id