ALTER TABLE concert_diary
ALTER COLUMN rating DROP NOT NULL;

INSERT INTO concert_diary (user_id, concert_id)
SELECT ca.user_id, ca.concert_id
FROM concert_attendance ca
JOIN concerts c ON c.id = ca.concert_id
WHERE ca.status = 'attending'
  AND COALESCE(c.end_datetime, c.start_datetime) < CURRENT_TIMESTAMP
ON CONFLICT (user_id, concert_id) DO NOTHING;