MongoDB multiple counts, single document, arrays - mongodb

Question

I have been searching on stackoverflow and cannot find exactly what I am looking for and hope someone can help. I want to submit a single query, get multiple counts back, for a single document, based on array of that document.
My data:
db.myCollection.InsertOne({
"_id": "1",
"age": 30,
"items": [
{
"id": "1",
"isSuccessful": true,
"name": null
},{
"id": "2",
"isSuccessful": true,
"name": null
},{
"id": "3",
"isSuccessful": true,
"name": "Bob"
},{
"id": "4",
"isSuccessful": null,
"name": "Todd"
}
]
});
db.myCollection.InsertOne({
"_id": "2",
"age": 22,
"items": [
{
"id": "6",
"isSuccessful": true,
"name": "Jeff"
}
]
});
What I need back is the document and the counts associated to the items array for said document. In this example where the document _id = "1":
{
"_id": "1",
"age": 30,
{
"totalIsSuccessful" : 2,
"totalNotIsSuccessful": 1,
"totalSuccessfulNull": 1,
"totalNameNull": 2
}
}
I have found that I can get this in 4 queries using something like this below, but I would really like it to be one query.
db.test1.aggregate([
{ $match : { _id : "1" } },
{ "$project": {
"total": {
"$size": {
"$filter": {
"input": "$items",
"cond": { "$eq": [ "$$this.isSuccessful", true ] }
}
}
}
}}
])
Thanks in advance.

Answer 1

I am assuming your expected result is invalid since you have an object literal in the middle of another object and also you have totalIsSuccessful for id:1 as 2 where it seems they should be 3. With that said ...
you can get similar output via $unwind and then grouping with $sum and $cond:
db.collection.aggregate([
{ $match: { _id: "1" } },
{ $unwind: "$items" },
{ $group: {
_id: "_id",
age: { $first: "$age" },
totalIsSuccessful: { $sum: { $cond: [{ "$eq": [ "$items.isSuccessful", true ] }, 1, 0 ] } },
totalNotIsSuccessful: { $sum: { $cond: [{ "$ne": [ "$items.isSuccessful", true ] }, 1, 0 ] } },
totalSuccessfulNull: { $sum: { $cond: [{ "$eq": [ "$items.isSuccessful", null ] }, 1, 0 ] } },
totalNameNull: { $sum: { $cond: [ { "$eq": [ "$items.name", null ]}, 1, 0] } } }
}
])
The output would be this:
[
{
"_id": "_id",
"age": 30,
"totalIsSuccessful": 3,
"totalNameNull": 2,
"totalNotIsSuccessful": 1,
"totalSuccessfulNull": 1
}
]
You can see it working here