How do I count of how many documents the field x is empty inside a certian collection? - arangodb

Question

I have problem. I have a collection orders. I want to check how many documents with the field phone are empty.
So how could I count of how many documents the field phone is empty inside the collection orders?
This my collection orders:
[
{'_id': 'orders/213123',
'contactEditor': {'name': 'Max Power',
'phone': '1234567',
'email': 'max#power.com'},
'contactSoldToParty': {'name': 'Max Not',
'phone': '123456789',
'email': 'maxnot#power.com'},
'isCompleteDelivery': False,
'metaData': {'dataOriginSystem': 'Goods',
'dataOriginWasCreatedTime': '10:12:12',},
'orderDate': '2021-02-22',
'orderDateBuyer': '2021-02-22',
},
{'_id': 'orders/12323',
'contactEditor': {'name': 'Max Power2',
'phone': '1234567',
'email': 'max#power.com'},
'contactSoldToParty': {'name': 'Max Not',
'phone': '123456789',
'email': 'maxnot#power.com'},
'isCompleteDelivery': False,
'metaData': {'dataOriginSystem': 'Goods',
'dataOriginWasCreatedTime': '10:12:12',},
'orderDate': '2021-02-22',
'orderDateBuyer': '2021-02-22',
},
]

Answer 1

If you're trying to FILTER for a value that is null...
FOR o IN orders
FILTER o.contactSoldToParty.phone == null
RETURN o
But if you just want a simple count, then I would use COLLECT (see the docs)...
FOR o IN orders
COLLECT hasPhone = (o.contactSoldToParty.phone != null) WITH COUNT INTO total
RETURN { hasPhone, total }
There are two caveats, both related to how your document is structured:
you may have to first check if the contactSoldToParty attribute exists (or use nullish coalescing)
be sure that the phone attribute is indeed empty/missing/null - null is not the same as an empty string ('')