scala - Anorm 查询，未找到展平

Question

在 yabe 示例中，有以下查询:

   def allWithAuthor:List[(Post,User)] = 
            SQL(
                """
                    select * from Post p 
                    join User u on p.author_id = u.id 
                    order by p.postedAt desc
                """
            ).as( Post ~< User ^^ flatten * )

在我的应用程序中，我有一个非常相似的查询:

def findAll:List[(Album,Artist)] = 
      SQL(
       """
           select * from Album al
           join Artist ar on al.artist_id = ar.id
           order by al.nbVotes desc
           limit 100
       """
      ).as( Album ~< Artist ^^ flatten * )

我有这个编译错误:

The file /app/models.scala could not be compiled. Error raised is : not found: 
value flatten Error occurred in an application involving default arguments.

我没有发现与 yabe 工作示例的区别......

你为什么我有这个错误？

Answer 1

按照评论中的建议，添加

import play.db.anorm.SqlParser._