elasticsearch only show where nested object has no values - elasticsearch

Question

I have the following structure (simplified):
{
"id": 100,
"vendorStatuses": [
{
"id": 200,
"status": "Open"
}
]
}
What I want to find is records where there are no vendor statuses. We recently upgraded from elasticseach 1.x to 5.x and I'm having trouble converting to get this functionality back.
My old Nest query looked like this:
!Filter<PurchaseOrder>.Nested(nfd => nfd.Path(x => x.VendorStatuses.First())
.Filter(f2 => f2.Missing(y => y.Id)));
The new query (now that Missing isn't available) looks like this so far:
Query<PurchaseOrder>
.Bool(z => z
.MustNot(a => a
.Exists(t => t
.Field(f => f.VendorStatuses)
)
)
);
Which generates this:
GET purchaseorder/_search
{
"query": {
"bool": {
"must_not": [
{
"exists": {
"field": "vendorStatuses",
}
}
]
}
}
}
But I'm still seeing results that have vendorStatuses records.
What am I doing wrong? I've tried searching for vendorStatuses.id or other fields, but it's not working. When I try to reverse the logic and do a must i see no results. I also tried doing it as a nested but couldn't get any closer with that.

Answer 1

The query using must_not and exists is not a nested query like the 1.x query. I think you're looking for something like
var query = Query<PurchaseOrder>
.Bool(z => z
.MustNot(a => a
.Nested(n => n
.Path(p => p.VendorStatuses)
.Query(nq => nq
.Exists(t => t
.Field(f => f.VendorStatuses)
)
)
)
)
);
client.Search<PurchaseOrder>(s => s.Query(_ => query));
which yields
{
"query": {
"bool": {
"must_not": [
{
"nested": {
"query": {
"exists": {
"field": "vendorStatuses"
}
},
"path": "vendorStatuses"
}
}
]
}
}
}
You can use operator overloading to make the query more succinct too
var query = !Query<PurchaseOrder>
.Nested(n => n
.Path(p => p.VendorStatuses)
.Query(nq => nq
.Exists(t => t
.Field(f => f.VendorStatuses)
)
)
);

Answer 2

I found a workaround that is far from ideal in my opinion. I created a new property on my PurchaseOrder model for NumberOfStatuses, then I just do a term search on that for value of 0.
public int NumberOfStatuses => VendorStatuses.OrEmptyIfNull().Count();
Query<PurchaseOrder>.Term(t => t.Field(po => po.NumberOfStatuses).Value(0));