One-to-many with lightweight many

Room lets you query for specific columns using a POJO with just those columns. (Incidentally, is @ColumnInfo necessary if the property name matches the column name?)

Documentation example:

data class NameTuple(
    @ColumnInfo(name = "first_name") val firstName: String?,
    @ColumnInfo(name = "last_name") val lastName: String?
)

// In DAO:
@Query("SELECT first_name, last_name FROM user")
fun loadFullName(): List<NameTuple>

When doing a one-to-many query, is there a way to select just a subset of columns from the dependent entity? All of the examples of relationships in the documentation show POJOs that combine the Entity classes into a POJO linking Entity classes, but not one of the non-entity tuples like above.

How do you tell it which columns to select in the implicit second query of the @Transaction?

I don't even know where to begin setting it up, or what the query code would be. For the sake of example, suppose you have a Person table and Pet table, and you want to be able to get a flow of all Persons with their pet's names, but none of the other pet data.

@Entity
data class Person(
    @PrimaryKey(autoGenerate = true) val id: Int = 0,
    val name: String = ""
)

@Entity
data class Pet(
    @PrimaryKey(autoGenerate = true) val id: Int = 0,
    val ownerId: Int = 0,
    val name: String = "",
    val animalType: String = "",
    val birthdate: Long = 0
)

// ...

data class PetName (
    @ColumnInfo(name = "id") val id: Int = 0,
    @ColumnInfo(name = "name") val name: String = ""
)

PersonWithPetsNames {
    @Embedded val person: Person,
    @Relation(parentColumn = "id", entityColumn = "ownerId", entity = Pet::class)
    val pets: List<PetName>
}

// in DAO:
@Transaction
@Query("SELECT * FROM Person ...???")
fun getPeopleWithPetNames(): Flow<List<PersonWithPetsNames>>