Use $gt operator to return document values among all the objects - mongodb

Question

This is one of many similar objects in shopping list collection. How do I do a query to get the list of only the "name" of people buying more than 2 "Noodles"?
Please help me figure this out, thanks in advance.
I assume this should have the $gt operator but I am not sure how to execute it correctly.
{
"_id" : ObjectId("591422529f75f9119575c1d8"),
"name" : "Hisham",
"age" : 20,
"address" : {
"house" : "HomeName",
"street" : "Fairyland",
"city" : "Faketon",
"pincode" : 000000
},
"itemlist" : [
{
"iname" : "Soap",
"quantity" : 2,
"price" : 10,
"rate" : 20,
"itemID" : "1"
},
{
"iname" : "Mirror",
"quantity" : 1,
"price" : 600,
"rate" : 600,
"itemID" : "4"
},
{
"iname" : "Noodles",
"quantity" : 4,
"price" : 50,
"rate" : 200,
"itemID" : "5"
},
{
"iname" : "Plug",
"quantity" : 2,
"price" : 50,
"rate" : 100,
"itemID" : "6"
}
]
}

Answer 1

you can achieve this with the aggregation framework like this :
db.collection.aggregate([
{
$unwind:"$itemlist"
},
{
$match:{
"itemlist.iname":"Noodles"
}
},
{
$group:{
_id:"$itemlist.iname",
name:{
$first:"$name"
},
count:{
$sum:1
}
}
},
{
$match:{
count:{
$gte:2
}
}
}
])
How it works:
unwind the itemlist array with $unwind
keep only Noodles item
count occurence of Noodles using $group
keep only document where count >= 2

Answer 2

You can select the all documents that match your criteria using the $elemMatch operator in the $match. From there all you need is a $group stage.
db.collection.aggregate([
{ "$match": {
"itemlist": {
"$elemMatch": {
"quantity": { "$gt": 2 },
"iname": "Noodles"
}
}
}},
{ "$group": { "_id": null, "names": { "$push": "$name" } } }
])