Develop Reference

Mongoose/MongoDB: How can I $inc only the first value I get from an array?

I have a Mongoose Schema that looks like this:
{
_id: ObjectID,
storage: [{
location: String,
storedFood: [{
code: String,
name: String,
weight: Number
}]
}]
}
And for example in storedFood can be the same Food twice. But I only want to update one of the weights of these items.
This is my code to $inc all of the items.... How can I reduce this to only one?
try {
const deletedFoodFromStorage = await User.updateOne(
{_id: user, "storage.location": location},
{ $inc: {"storage.$.storedFood.$[food].weight": -weight}},
{ arrayFilters: [ { "food.code": code } ]},
);
res.json(deletedFoodFromStorage);
} catch(err) {
res.status(400).json('Error: ' + err)
}

Should have been a simple one. Only way I found at the moment is not simple:
db.collection.update(
{_id: user, "storage.location": location},
[
{$set: {
newItem: {
$reduce: {
input: {$getField: {
input: {$first: {$filter: {
input: "$storage",
as: "st",
cond: {$eq: ["$$st.location", location]}
}}},
field: "storedFood"
}},
initialValue: [],
in: {$concatArrays: [
"$$value",
{$cond: [
{$and: [
{$eq: ["$$this.code", code]},
{$not: {$in: [code, "$$value.code"]}}
]},
[{$mergeObjects: [
"$$this",
{weight: {$subtract: ["$$this.weight", weight]}}
]}],
["$$this"]
]
}
]
}
}
}
}},
{$set: {
storage: {
$map: {
input: "$storage",
in: {$cond: [
{$eq: ["$$this.location", location]},
{$mergeObjects: ["$$this", {storedFood: "$newItem"}]},
"$$this"
]}
}
},
newItem: "$$REMOVE"
}}
])
See how it works on the playground example

Borrowing liberally from nimrod serok's answer, here's one way to do it with a single pass through all the arrays. I suspect this can be improved, at least for clarity.
db.collection.update({
_id: user,
"storage.location": location
},
[
{
"$set": {
"storage": {
"$map": {
"input": "$storage",
"as": "store",
"in": {
"$cond": [
{"$ne": ["$$store.location", location]},
"$$store",
{
"$mergeObjects": [
"$$store",
{
"storedFood": {
"$getField": {
"field": "theFoods",
"input": {
"$reduce": {
"input": "$$store.storedFood",
"initialValue": {
"incOne": false,
"theFoods": []
},
"in": {
"$cond": [
"$$value.incOne",
{
"incOne": "$$value.incOne",
"theFoods": {
"$concatArrays": [
"$$value.theFoods",
["$$this"]
]
}
},
{
"$cond": [
{"$ne": ["$$this.code", code]},
{
"incOne": "$$value.incOne",
"theFoods": {
"$concatArrays": [
"$$value.theFoods",
["$$this"]
]
}
},
{
"incOne": true,
"theFoods": {
"$concatArrays": [
"$$value.theFoods",
[
{
"$mergeObjects": [
"$$this",
{"weight": {"$add": ["$$this.weight", -weight]}}
]
}
]
]
}
}
]
}
]
}
}
}
}
}
}
]
}
]
}
}
}
}
}
])
Try it on mongoplayground.net.

Ty for your help!
The final solution for me was to restructure addStoredFood-Function to make the storedFood unique and only add weight to it instead of adding another objects.
This makes my old update-Function work aswell.

Unable to make the right query in Mongodb

I want to group by name then find the percentage of count of fill document to total document. The data is given below,here(fill:0 means not fill):-
{"name":"Raj","fill":0}
{"name":"Raj","fill":23}
{"name":"Raj","fill":0}
{"name":"Raj","fill":43}
{"name":"Rahul","fill":0}
{"name":"Rahul","fill":23}
{"name":"Rahul","fill":0}
{"name":"Rahul","fill":43}
{"name":"Rahul","fill":43}
{"name":"Rahul","fill":43}
Result :-
{
"name":"Raj",
fillcount:2,
fillpercentagetototaldocument:50% // 2 (fill count except 0 value ) divide by 4(total document for raj)
}
{
"name":"Rahul",
fillcount:4,
fillpercentagetototaldocument:66% // 4(fill count except 0 value ) divide by 6(total document for rahul)
}

You want you use $group combined with a conditional count like so:
db.collection.aggregate([
{
$group: {
_id: "$name",
total: {
$sum: 1
},
fillcount: {
$sum: {
$cond: [
{
$ne: [
"$fill",
0
]
},
1,
0
]
}
}
}
},
{
$project: {
_id: 0,
name: "$_id",
fillcount: 1,
fillpercentagetototaldocument: {
"$multiply": [
{
"$divide": [
"$fillcount",
"$total"
]
},
100
]
}
}
}
])
Mongo Playground

You can use mongos aggregation function to achieve that.
example:
db.getCollection('CollectionName').aggregate([
{
$group: {
_id: { name: '$name'},
fillpercentagetototaldocument: { $sum: '$fill' },
fillCount:{$sum:1}
},
},
{ $sort: { fillpercentagetototaldocument: -1 } },
]);
The result will look like this afterwards:
[
{
"_id" : {
"name" : "Rahul"
},
"fillpercentagetototaldocument" : 152,
"fillCount" : 6.0
},
{
"_id" : {
"name" : "Raj"
},
"fillpercentagetototaldocument" : 66,
"fillCount" : 4.0
}
]

Find duplicate values inside an array in Mongo DB but it can be present outside object

{
"_id" : ObjectId("15672"),
"userName" : "4567",
"library" : [
{
"serialNumber" : "Book_1"
},
{
"serialNumber" : "Book_2"
},
{
"serialNumber" : "Book_4"
}
]
},
{
"_id" : ObjectId("123456"),
"userName" : "123",
"library" : [
{
"serialNumber" : "Book_2"
}
]
},
{
"_id" : ObjectId("1835242"),
"userName" : "13526",
"library" : [
{
"serialNumber" : "Book_7"
},
{
"serialNumber" : "Book_6"
},
{
"serialNumber" : "Book_5"
},
{
"serialNumber" : "Book_4"
},
{
"serialNumber" : "Book_3"
},
{
"serialNumber" : "Book_5"
}
]
}
I want a query which will give me the username in which serialNumber values are duplicate. The serial number values in one library can be present in other username library but it should not be there in one particular username library

Try this query :
db.collection.aggregate([
/** First match stage is optional if all of your docs are of type array & not empty */
{ $match: { $expr: { $and: [{ $eq: [{ $type: "$library" }, "array"] }, { $ne: ["$library", []] }] } } },
/** Add a new field allUnique to each doc, will be false where if elements in library have duplicates */
{
$addFields: {
allUnique: {
$eq: [
{
$size:
{
$reduce: {
input: "$library.serialNumber",
initialValue: [], // start with empty array
/** iterate over serialNumber's array from library & push current value if it's not there in array, at the end reduce would produce an array with uniques */
in: { $cond: [{ $in: ["$$this", "$$value"] }, [], { $concatArrays: [["$$this"], "$$value"] }] }
}
}
},
{
$size: "$library"
}
]
}
}
},
/** get docs where allUnique: false */
{
$match: {
allUnique: false
}
},
/** Project only needed fields & remove _id which is bydefault projected */
{
$project: {
userName: 1,
_id: 0
}
}
])
Other option can be doing this through $unwind but which is not preferable on huge datasets as it explodes your collection.
Test : MongoDB-Playground
Or from answer of #Dennis in this link duplicate-entries-from-an-array , You can try as below :
db.collection.aggregate([
{
$match: {
$expr: {
$and: [
{
$eq: [
{
$type: "$library"
},
"array"
]
},
{
$ne: [
"$library",
[]
]
}
]
}
}
},
{
$addFields: {
allUnique: {
$eq: [
{
$size: {
"$setUnion": [
"$library.serialNumber",
[]
]
}
},
{
$size: "$library"
}
]
}
}
},
{
$match: {
allUnique: false
}
},
{
$project: {
userName: 1,
_id: 0
}
}
])
Test : MongoDB-Playground

How to use $filter in nested child array with mongodb?

My mongodb data is like this,i want to filter the memoryLine.
{
"_id" : ObjectId("5e36950f65fae21293937594"),
"userId" : "5e33ee0b4a3895a6d246f3ee",
"notes" : [
{
"noteId" : ObjectId("5e36953665fae212939375a0"),
"time" : ISODate("2020-02-02T17:24:06.460Z"),
"memoryLine" : [
{
"_id" : ObjectId("5e36953665fae212939375ab"),
"memoryTime" : ISODate("2020-02-03T17:54:06.460Z")
},
{
"_id" : ObjectId("5e36953665fae212939375aa"),
"memoryTime" : ISODate("2020-02-03T05:24:06.460Z")
}
]
}
]}
i want to get the item which memoryTime is great than now as expected like this,
"userId" : "5e33ee0b4a3895a6d246f3ee",
"notes" : [
{
"noteId" : ObjectId("5e36953665fae212939375a0"),
"time" : ISODate("2020-02-02T17:24:06.460Z"),
"memoryLine" : [
{
"_id" : ObjectId("5e36953665fae212939375ab"),
"memoryTime" : ISODate("2020-02-03T17:54:06.460Z")
},
{
"_id" : ObjectId("5e36953665fae212939375aa"),
"memoryTime" : ISODate("2020-02-03T05:24:06.460Z")
}
]
}]
so is use code as below.i use a $filter in memoryLine to filter to get the right item.
aggregate([{
$match: {
"$and": [
{ userId: "5e33ee0b4a3895a6d246f3ee"},
]
}
}, {
$project: {
userId: 1,
notes: {
noteId: 1,
time: 1,
memoryLine: {
$filter: {
input: "$memoryLine",
as: "mLine",
cond: { $gt: ["$$mLine.memoryTime", new Date(new Date().getTime() + 8 * 1000 * 3600)] }
}
}
}
}
}]).then(doc => {
res.json({
code: 200,
message: 'success',
result: doc
})
});
but i got this,memoryLine is null,why?I try to change $gt to $lt, but also got null.
"userId" : "5e33ee0b4a3895a6d246f3ee",
"notes" : [
{
"noteId" : ObjectId("5e36953665fae212939375a0"),
"time" : ISODate("2020-02-02T17:24:06.460Z"),
"memoryLine" : null <<<------------- here is not right
}]

You can use $addFields to replace existing field, $map for outer collection and $filter for inner:
db.collection.aggregate([
{
$addFields: {
notes: {
$map: {
input: "$notes",
in: {
$mergeObjects: [
"$$this",
{
memoryLine: {
$filter: {
input: "$$this.memoryLine",
as: "ml",
cond: {
$gt: [ "$$ml.memoryTime", new Date() ]
}
}
}
}
]
}
}
}
}
}
])
$mergeObjects is used to avoid repeating fields from source memoryLine object.
Mongo Playground

How to get the value repetition count on array of objects for all entries on mongodb aggregation

I have the data structure like this:
{
"_id" : ObjectId("5c4404906736bd2608e30b5e"),
"assets": [
{
"name" : "xa",
"id" : 1
},
{
"name" : "xs",
"id" : 2
}
]
},
{
"_id" : ObjectId("5c4404906736bd2608e30b5f"),
"assets": [
{
"name" : "xa",
"id" : 3
}
]
},
{
"_id" : ObjectId("5c4404906736bd2608e30b5g"),
"assets": [
{
"name" : "xa",
"id" : 4
},
{
"name" : "xd",
"id" : 5
},
{
"name" : "xs",
"id" : 6
}
]
}
Now I want to implement the MongoDB aggregation by which I got the Answer like this:
[
{
"assets": "xa",
"count": 3
},
{
"assets": "xs",
"count": 2
},
{
"assets": "xd",
"count": 1
},
]
I have to get this done by javascript but need to implement this on aggregation. My code for acheiveing with js is like this for set of array of object i.e
var arr = [
{ asset: "xa" },
{ asset: "xs" },
{ asset: "xa" },
{ asset: "xs" },
{ asset: "xa" },
{ asset: "xd" }
];
var userDict = arr.reduce((acc, el) => {
if (!acc.hasOwnProperty(el.asset)) {
acc[el.asset] = { count: 0 };
}
acc[el.asset].count++;
return acc;
}, {});
var result = Object.entries(userDict).map(([k, v]) => ({
asset: k,
count: v.count
}));
console.log(result);
Any help is really appreciated

You can $unwind assets before applying $group with count:
db.col.aggregate([
{
$unwind: "$assets"
},
{
$group: {
_id: "$assets.name",
count: { $sum: 1 }
}
},
{
$project: {
_id: 0,
asset: "$_id",
count: 1
}
}
])