select c.id candidate_id
  , c.name, c.test_hash
  , q.quiz_id, q.id question_id, a.id answer_id, q.sort
  , q.question, q.category, q.input_type, q.input_options, a.answer
  , ifnull(a.saved, false) saved, ifnull(a.submitted, false) submitted , a.updated_at
from candidates c
  inner join questions q on q.quiz_id = c.quiz_id
  left join answers a on a.candidate_id = c.id AND a.question_id = q.id
order by c.name, q.sort;