a (id, first, second, third)
b (id, whatever)

SELECT * FROM a WHERE id NOT IN (SELECT id FROM b)

SELECT *
FROM a
WHERE NOT EXISTS (SELECT 1 FROM b WHERE b.id=a.id)

SELECT *
FROM a
LEFT JOIN b ON b.id=a.id
WHERE b.id is null
GROUP BY a.id

select * from a where a.id not in (select distinct id from b)