在使用Room数据库的Android应用程序中,使用表B上的内部联接查询表A不会返回表B中的列

我正试着向你询问 posts 打开内部联接的表 users 及其各自的主键和外键:

@Query("SELECT p.*, u.id AS userId, u.name AS userName, u.username AS userUsername FROM posts p JOIN users u ON p.userId = u.id")
fun fetchAllPostsAndUsers(): Observable<List<Post>>

这些是POJO。第一, User :

@Entity(tableName = "users")
data class User(
    @PrimaryKey(autoGenerate = true)
    @SerializedName("id")
    @ColumnInfo(name = "id")
    val uid: Int,

    val name: String,

    val username: String,

    val email: String,

    @Embedded
    val address: Address?,

    val phone: String,

    val website: String,

    @Embedded
    val company: Company?
)

Post :

@Entity(
    tableName = "posts",
    foreignKeys = [ForeignKey(
        entity = User::class,
        parentColumns = ["id"],
        childColumns = ["userId"],
        onDelete = ForeignKey.CASCADE
    )]
)
data class Post(
    @PrimaryKey(autoGenerate = true)
    @SerializedName("id")
    @ColumnInfo(name = "id")
    val pid: Int,

    val userId: Int,

    val title: String,

    val body: String
)

但是上面查询的结果只是 帖子 使用者 ,尽管从数据库获取时已包含在查询中。