firebase - Flutter/Dart QuerySnapshot isEqualTo还是运算符？

Question

我想问一下集合中是否有一个文档，其“test”字段等于1 2或4。但是很遗憾，我没有找到合适的解决方案。

这是我的方法不幸的是，这在这里不起作用(等于1 | 2 | 4)。是否还是运算符？ (|)

Future getPostsToday() async { 
   ...
    var firestore =  Firestore.instance;
    QuerySnapshot qn = await firestore.collection("Data").where("test",   isEqualTo: 1 | 2 | 4 ).getDocuments();
    return qn.documents;  
 }

Answer 1

Cloud Firestore does not support the following types of queries:

• Logical OR queries. In this case, you should create a separate query for each OR condition and merge the query results in your app.

资料来源: Query limitations

编辑:

因此，我认为您可以执行以下操作:

Future<List<DocumentSnapshot>> getPostsToday() async {
  final collection = Firestore.instance.collection("Data");

  // separate query for each OR condition
  final querySnapshots = await Future.wait([
    collection.where("test", isEqualTo: 1).getDocuments(),
    collection.where("test", isEqualTo: 2).getDocuments(),
    collection.where("test", isEqualTo: 4).getDocuments(),
  ]);

  // merge the query results and return
  return <DocumentSnapshot>[
    ...querySnapshots[0].documents,
    ...querySnapshots[1].documents,
    ...querySnapshots[2].documents,
  ];
}