Firestore: How to get all documents where a specific field exist-CodePudding

I have a collection in Firestore where some documents contain an array but some don't. The structure looks like this:

document1 = {
    date: '2022-02-02',
    name: 'x',
    array: ['a'],
}   

document2 = {
    date: '2022-02-03',
    name: 'y',
}

How can I get all documents where the field arrayexists? So in this example only document1?

Is any of these solutions possible:

db.collection('employees').where(`array`, '!=', null).get();

db.collection('employees').where(`array`, '>=', []).get();

CodePudding user response：

How can I get all documents where the field array exists?

When you add data to Firestore make sure to provide a null value for the array field like this:

document1 = {
    date: '2022-02-02',
    name: 'x',
    array: null,
}

In this way, the following query will work perfectly fine:

db.collection('employees').where(`array`, '!=', null).get();

If it's an ongoing project, and the array field doesn't exist at all, then simply update the existing documents with the array holding a null value. This is possible because null is a supported data type in Firestore.

CodePudding user response：

First of all you should try your solutions.

If they dont work, you can try to loop through your documents and check if doc.data().array exists