Two columns in subquery in where clause

Question

I have a query:

SELECT s.period, s.year, s.amount 
FROM salaries s

I would like to select from salaries table only the rows th

Answer 1

You can use more than one column for an IN condition:

SELECT s.period, s.year, s.amount 
FROM salaries s
where (s.year, s.period) in (select year, period from periods)

But Gordon's not exists solution is probably faster.