如何在Firestore数据库中与AngularFireBase库进行内连接？

npm install @angular/fire firebase --save

import { AngularFireModule } from '@angular/fire';
import { AngularFireDatabaseModule } from '@angular/fire/database';

const firebaseConfig = {
  apiKey: 'YOUR_API_KEY',
  authDomain: 'YOUR_AUTH_DOMAIN',
  databaseURL: 'YOUR_DATABASE_URL',
  projectId: 'YOUR_PROJECT_ID',
  storageBucket: 'YOUR_STORAGE_BUCKET',
  messagingSenderId: 'YOUR_MESSAGING_SENDER_ID',
  appId: 'YOUR_APP_ID'
};

@NgModule({
  imports: [
    AngularFireModule.initializeApp(firebaseConfig),
    AngularFireDatabaseModule
  ],
  // 其他模块配置...
})
export class AppModule { }

import { Component, OnInit } from '@angular/core';
import { AngularFireDatabase } from '@angular/fire/database';
import { Observable } from 'rxjs';

@Component({
  selector: 'app-example',
  templateUrl: './example.component.html',
  styleUrls: ['./example.component.css']
})
export class ExampleComponent implements OnInit {
  items: Observable<any[]>;

  constructor(private db: AngularFireDatabase) { }

  ngOnInit() {
    // 执行内连接操作
    const collection1 = this.db.collection('collection1');
    const collection2 = this.db.collection('collection2');
    
    this.items = collection1.doc('document1').valueChanges()
      .pipe(switchMap(data1 => {
        return collection2.doc('document2').valueChanges()
          .pipe(map(data2 => {
            // 执行内连接逻辑
            // ...
          }));
      }));
  }
}