Flutter Firestore: :How I can order firestore query by field/value inside map?-CodePudding

I tried:

FirebaseFirestore.instance
        .collection('messages')                  
        .orderBy('sentDate', descending: false)
        .snapshots(),

but it didn't work.

Firebase Firestore collection/path

CodePudding user response：

If you want to order by the sendDate of a specific entry in the map you can using dot notation:

.orderBy('167361790.sentDate', descending: false)

If you want to sort on the sentDate of a dynamically selected map entry, that isn't possible with your current data model, and you'll want to modify your data model to allow the use-case.

For example, if you want to order the messages on the most recent sentDate, you should add a top-level field to the document latestSentDate, update that whenever you write to the map, and then sort on that.