create index if not exists idx_practice_sessions_user_started
  on public.practice_sessions(tenant_id, user_id, started_at desc);

create index if not exists idx_practice_sessions_user_finished
  on public.practice_sessions(tenant_id, user_id, finished_at desc)
  where finished_at is not null;

create index if not exists idx_answer_records_user_answered
  on public.answer_records(tenant_id, user_id, answered_at desc);

create index if not exists idx_answer_records_session_latest
  on public.answer_records(tenant_id, user_id, practice_session_id, question_id, answered_at desc);

create index if not exists idx_wrong_questions_user_review
  on public.wrong_questions(tenant_id, user_id, resolved_at, last_wrong_at desc, wrong_count desc);

create index if not exists idx_favorite_questions_user_created
  on public.favorite_questions(tenant_id, user_id, created_at desc);