Sum from array object value by mongodb - mongodb

Question

I am trying to solve a problem. I want to write a query that finds a document among my documents which one is greater by the sum of columns A and B's in an array. I write an example down here. I am new to MongoDB and I've been searching a lot but I could not find my solution. So can somebody help me to solve this problem? Here are my sample documents:
document1:
{
"_id" : "1",
"array": [
{
"user": "1",
"A": 2,
"B": 0
},
{
"user": "2",
"A": 3,
"B": 1},
{
"user": "3",
"A": 0,
"B": 5
}
]
}
and document 2:
{
"_id" : "2",
"array": [
{
"user": "4",
"A": 1,
"B": 1
},
{
"user": "5",
"A": 2,
"B": 2
}
]
}
for example, the sum of A and B's in all elements of an array in document 1 is 11 and the sum of A and B's in elements of an array in document 2 is 6. So I want to get document 1 for output because it is greater than 2 after summing all A and B's in all of the elements.

Answer 1

You can try this query:
Create an auxiliar field called total (or whatever name you want) and $add values. This add the $sum of the arrays. That means here you are adding all values from A and B together.
Then sort by the auxiliar field to get the greatest at first position
$limit to only one (the greatest)
And $project to not output the auxiliar field.
db.collection.aggregate([
{
"$addFields": {
"total": {
"$add": [
{
"$sum": "$array.A"
},
{
"$sum": "$array.B"
}
]
}
}
},
{
"$sort": {
"total": -1
}
},
{
"$limit": 1
},
{
"$project": {
"total": 0
}
}
])
Example here