Thanks! It works:
"foo"
|> with_cte("foo", as: fragment("""
SELECT * FROM (VALUES (1,2),(3,4)) AS foo (x,y)
"""))
|> select([foo], {foo.x, foo.y})
|> Repo.all()
[debug] QUERY OK source="foo" db=2.7ms queue=0.6ms idle=1721.4ms
WITH "foo" AS (SELECT * FROM (VALUES (1,2),(3,4)) AS foo (x,y)) SELECT f0."x", f0."y" FROM "foo" AS f0 []
[{1, 2}, {3, 4}]
