sql query for posts with multiple comment conditions

gistfile1.sql

SELECT "posts".* FROM "posts"
WHERE
  "posts"."id" IN
    (SELECT post_id FROM "posts"
      INNER JOIN "comments" ON "comments"."post_id" = "posts"."id"
      WHERE "comments"."title" = 'foo')
AND
  "posts"."id" IN
    (SELECT post_id FROM "posts"
      INNER JOIN "comments" ON "comments"."post_id" = "posts"."id"
      WHERE "comments"."title" = 'bar')