Scala Slick 3-如何在joinLeft上获得不匹配的结果？

import slick.jdbc.H2Profile.api._

case class User(id: Int, name: String)
case class Order(id: Int, userId: Int, product: String)

class Users(tag: Tag) extends Table[User](tag, "users") {
  def id = column[Int]("id", O.PrimaryKey)
  def name = column[String]("name")
  def * = (id, name) <> (User.tupled, User.unapply)
}

class Orders(tag: Tag) extends Table[Order](tag, "orders") {
  def id = column[Int]("id", O.PrimaryKey)
  def userId = column[Int]("user_id")
  def product = column[String]("product")
  def * = (id, userId, product) <> (Order.tupled, Order.unapply)
}

val users = TableQuery[Users]
val orders = TableQuery[Orders]

val query = for {
  (user, order) <- users joinLeft orders on (_.id === _.userId)
} yield (user, order)

val db = Database.forConfig("h2mem1")
db.run(query.result).foreach { result =>
  result.foreach {
    case (user, Some(order)) => println(s"User: ${user.name}, Order: ${order.product}")
    case (user, None) => println(s"User: ${user.name}, No Orders")
  }
}

val query = for {
  (user, order) <- users joinLeft orders on (_.id === _.userId)
} yield (user, order)

db.run(query.result).foreach { result =>
  result.foreach {
    case (user, Some(order)) => println(s"User: ${user.name}, Order: ${order.product}")
    case (user, None) => println(s"User: ${user.name}, No Orders")
  }
}