Query on non empty object field having multiple keys or to check size of object greater than 1

[Prasad_Saya]

@Aamod_Pisat

What I want is I would like to get that any other exists than given key in object field or I want is if that object has multiple keys or not i.e size of object length should be greater than 1.
So, for that, we used $gt operator. So, is that the right thing to do

That is not the right query for it.

You have to write an aggregation query and use the $objectToArray aggregation operator to convert the object as an array and then find the length of the array. If the length of the array is greater than 1, then there are more than one field in the object. See the example from the documentation explains how to convert the object to an array.