[FireStore Question] What's difference between Unary.IsNull and Binary.Equal null ? Are there Unary.NotNull?

What’s difference between Unary.IsNull and Binary.Equal null ?

Is it has any difference behavior? Can we use it to find document that has specific field exist or not exist?

At first I look at UnaryOperator to find operator for NotNull

I have document like this

{
    "_id" : "1",
    "result" : {}
}
{
    "_id" : "2"
}
{
    "_id" : "3",
    "result" : {}
}

I want to query for all document that already has any result. And also I want to query for any document that don’t has any result yet too, how should I make query?

[schmidt-sebastian]

Firestore distinguishes between two kind of queries. Most types allow inequality comparisons (such as >=), but NaN and Null only allows for equality. In this specific example, you can work around this with startAfter. For now, where("a",">=",null) unfortunately does not work directly.

[schmidt-sebastian]

Yes, you can sort types against one another. Specifying > null would return everything that is defined and not null since null sorts first in Firestore. I don’t know out of the top of my head if we have any publicly available documentation on our ordering semantics, but you can take a look here to see how types compare: https://github.com/googleapis/nodejs-firestore/blob/master/src/order.js#L29