如何将Firebase中的查询过滤到我的帖子的子级中的特定字段？- Firebase & Swift

import Firebase
import FirebaseDatabase

FirebaseApp.configure()

let databaseRef = Database.database().reference()

- posts
  - post1
    - title: "Post 1"
    - category: "News"
  - post2
    - title: "Post 2"
    - category: "Tutorial"
  - post3
    - title: "Post 3"
    - category: "News"

let query = databaseRef.child("posts").queryOrdered(byChild: "category").queryEqual(toValue: "News")

query.observe(.value) { (snapshot) in
    // 处理查询结果
    for childSnapshot in snapshot.children {
        if let postSnapshot = childSnapshot as? DataSnapshot {
            let post = postSnapshot.value as? [String: Any]
            let title = post?["title"] as? String
            print("Title: \(title ?? "")")
        }
    }
}