multiple where query in firestore queryBuilder

问题

I just noticed today that whenever I want to query a database I get an error which doesn't really make a sense to me and querying just stop working. It worked just fine few weeks ago.

Invalid Query. All where filters with an inequality (lessThan, lessThanOrEqual, greaterThan, or greaterThanOrEqual) must be on the same field. But you have inequality filters on 'value1' and 'value2')

  Stream<List<MyModel>> myStream(
      {MyFilter filter, String category}) {
    return _service.collectionsStream(
        path: APIPath.tools(cid, category),
        queryBuilder: filter != null
            ? (query) => query
                .where('value1', isGreaterThan: filter.minValue1)
                .where('value1', isLessThan: filter.maxValue1)
                .where('value2', isLessThan: filter.maxValue2)
                .where('value2', isGreaterThan: filter.minValue2)
            : null,
        builder: (data, documentID) => MyModel.fromMap(data, documentID),
        sort: (lhs, rhs) => lhs.value1.compareTo(rhs.value1));
  }

Am I doing something wrong? What does that error means and why I didn't get it last time?

回答1:

A Firestore query can only contain relational conditions (>, <, etc) on a single field. From the documentation on query limitations:

Queries with range filters on different fields are not supported.

So you'll have to choose which field you want Firestore to perform a range filter on. You'll then have to do the others in your application code.

To learn more about why this limit exists, and on working within Firestore's limitations to implement use-cases, I highly recommend checking out the video series Getting to know Cloud Firestore.

回答2:

With firebase you can't do a query on multiples fields of a document. So in your case you can't do a query on 'value1' AND 'value2', you have to do a query on 'value1' and after, filter in intern your query to match 'value2'.

Example:

//your query code 
queryBuilder: filter != null
            ? (query) => query             
                .where('value2', isGreaterThan: filter.minValue2)
                .where('value2', isLessThan: filter.maxValue2)
                ...
            : null,
//your query code

myQuery = querySnapshot.documents.where((document) => document.data['value1'] > filter.minValue1).toList();

来源：https://stackoverflow.com/questions/61306009/multiple-where-query-in-firestore-querybuilder