joinexample.sql

explain with a (id, num) as (values
    (1, 10)
  , (2, 20)
  , (4, 40)
  , (5, 50)
)

, b (id, num) as (values
    (1, 100)
  , (2, 200)
  , (3, 300)
  , (4, 400)
  , (5, 500)
)

, combo as (
  select a.num as a, b.num as b
  from a 
  left outer join b on a.id = b.id
)

select a from combo;