In mongodb, if we want to take first or last document of the group stage, then the FIRST and LAST operator will helpful. I want to group the collection based on _id:"$department" and also take the LAST document and the LAST-1 document. Is there any way to achieve this.
Assume you have this collection:
[
{ department: "HR", employees: 20 },
{ department: "Finance", employees: 30 },
{ department: "Sales", employees: 5 },
{ department: "IT", employees: 50 }
]
Then you can run this aggregation:
db.collection.aggregate([
{ $sort: { department: 1 } },
{
$group: {
_id: null,
employees: { $sum: "$employees" },
all_departments: { $push: "$department" }
}
},
{
$set: {
last_departments: {
$concatArrays: [
[{ $arrayElemAt: ["$all_departments", -1] }],
[{ $arrayElemAt: ["$all_departments", -2] }]
]
}
}
}
])
Mongo Playground
Update
With $slice it is even shorter:
db.collection.aggregate([
{ $sort: { department: 1 } },
{
$group: {
_id: null,
employees: { $sum: "$employees" },
all_departments: { $push: "$department" }
}
},
{ $set: { last_departments: { $slice: ["$all_departments", -2] } } }
])
Related
I have below data in my collection:
[
{
"_id":{
"month":"Jan",
"year":"2022"
},
"products":[
{
"product":"ProdA",
"status":"failed",
"count":15
},
{
"product":"ProdA",
"status":"success",
"count":5
},
{
"product":"ProdB",
"status":"failed",
"count":20
},
{
"product":"ProdB",
"status":"success",
"count":10
}
]
},
...//more such data
]
I want to group the elements of products array on the name of the product, so that we have record of how what was the count of failure of success of each product in each month. Every record is guaranteed to have both success and failure count each month. The output should look like below:
[
{
"_id":{
"month":"Jan",
"year":"2022"
},
"products":[
{
"product":"ProdA","status":[{"name":"success","count":5},{"name":"failed","count":15}]
},
{
"product":"ProdB","status":[{"name":"success","count":10},{"name":"failed","count":20}]
}
]
},
...//data for succeeding months
]
I have tried to do something like this:
db.collection.aggregate([{ $unwind: "$products" },
{
$group: {
"_id": {
month: "$_id.month",
year: "$_id.year"
},
products: { $push: { "product": "$product", status: { $push: { name: "$status", count: "$count" } } } }
}
}]);
But above query doesn't work.
On which level I need to group fields so as to obtain above output.
Please help me to find out what I am doing wrong.
Thank You!
Your first group stage needs to group by both the _id and the product name, aggregate a list of status counts and then another group stage which then forms the products list:
db.collection.aggregate([
{$unwind: "$products"},
{$group: {
_id: {
id: "$_id",
product: "$products.product",
},
status: {
$push: {
name: "$products.status",
count: "$products.count"
}
}
}
},
{$group: {
_id: "$_id.id",
products: {
$push: {
product: "$_id.product",
status: "$status"
}
}
}
}
])
Mongo Playground
I have grouped all the users by country, but I would also like to have a row showing the grand total (users are tagged to a single country in our use case).
Data Model / Sample Input
The collection is filled with objects representing a country (name) and each contains a list of user objects in an array under users.
{ _id: ObjectId("..."),
name: 'SG',
type: 'COUNTRY',
increment: 200,
users:
[ ObjectId("..."),
ObjectId("..."),
...
Query
db.collection.aggregate([{$match:{type:"COUNTRY"}},{$unwind:"$users"},{$sortByCount:"$name"}])
Current Results
{ _id: 'SG', count: 76 }
{ _id: 'IN', count: 6 }
{ _id: 'US', count: 4 }
{ _id: 'FR', count: 3 }
{ _id: 'UK', count: 2 }
{ _id: 'RU', count: 1 }
{ _id: 'CO', count: 1 }
{ _id: 'DK', count: 1 }
{ _id: 'ID', count: 1 }
{ _id: 'PH', count: 1 }
Expected Results
{ _id: 'SG', count: 76 }
{ _id: 'IN', count: 6 }
{ _id: 'US', count: 4 }
{ _id: 'FR', count: 3 }
{ _id: 'UK', count: 2 }
{ _id: 'RU', count: 1 }
{ _id: 'CO', count: 1 }
{ _id: 'DK', count: 1 }
{ _id: 'ID', count: 1 }
{ _id: 'PH', count: 1 }
{ _id: null, count: 96 } <<< TOTAL COUNT ADDED
Any tips to achieve this without resorting to complex or dirty tricks?
You can also try using $facet to calculate counts by country name and total count, and then combine them together. Something like this:
db.collection.aggregate([
{
$match: {
type: "COUNTRY"
}
},
{
"$unwind": "$users"
},
{
"$facet": {
"groupCountByCountry": [
{
"$sortByCount": "$name"
}
],
"totalCount": [
{
"$group": {
"_id": null,
"count": {
"$sum": 1
}
}
}
]
}
},
{
"$project": {
array: {
"$concatArrays": [
"$groupCountByCountry",
"$totalCount"
]
}
}
},
{
"$unwind": "$array"
},
{
"$replaceRoot": {
"newRoot": "$$ROOT.array"
}
}
])
Here's the playground link.
I recommend just doing this in memory as the alternative is "hacky" but in order to achieve this in Mongo you just need to group all documents, add a new documents and unwind again, like so:
db.collection.aggregate([
{
$group: {
_id: null,
roots: {
$push: "$$ROOT"
},
sum: {
$sum: "$count"
}
}
},
{
$addFields: {
roots: {
"$concatArrays": [
"$roots",
[
{
_id: null,
count: "$sum"
}
]
]
}
}
},
{
$unwind: "$roots"
},
{
$replaceRoot: {
newRoot: "$roots"
}
}
])
Mongo Playground
I'm trying to get the result in some form using mongodb aggregation.
here is my sample document in the collection:
[{
"_id": "34243243243",
"workType": "TESTWORK1",
"assignedDate":ISODate("2021-02-22T00:00:00Z"),
"status":"Completed",
},
{
"_id": "34243243244",
"workType": "TESTWORK2",
"assignedDate":ISODate("2021-02-21T00:00:00Z"),
"status":"Completed",
},
{
"_id": "34243243245",
"workType": "TESTWORK3",
"assignedDate":ISODate("2021-02-20T00:00:00Z"),
"status":"InProgress",
}...]
I need to group last 5 days data in an array by workType count having staus completed.
Expected result:
{_id: "TESTWORK1" , value: [1,0,4,2,3] ,
_id: "TESTWORK2" , value: [3,9,,3,5],
_id : "TESTWORK3", value: [,,,3,5]}
Here is what I'm trying to do, but not sure how to get the expected result.
db.testcollection.aggregate([
{$match:{"status":"Completed"}},
{$project: {_id:0,
assignedSince:{$divide:[{$subtract:[new Date(),$assignedDate]},86400000]},
workType:1
}
},
{$match:{"assignedSince":{"lte":5}}},
{$group : { _id:"workType", test :{$push:{day:"$assignedSince"}}}}
])
result: {_id:"TESTWORK1": test:[{5},{3}]} - here I'm getting the day , but I need the count of the workTypes on that day.
Is there any easy way to do this? Any help would be really appreciated.
Try this:
db.testcollection.aggregate([
{
$match: { "status": "Completed" }
},
{
$project: {
_id: 0,
assignedDate: 1,
assignedSince: {
$toInt: {
$divide: [{ $subtract: [new Date(), "$assignedDate"] }, 86400000]
}
},
workType: 1
}
},
{
$match: { "assignedSince": { "$lte": 5 } }
},
{
$group: {
_id: {
workType: "$workType",
assignedDate: "$assignedDate"
},
count: { $sum: 1 }
}
},
{
$group: {
_id: "$_id.workType",
values: { $push: "$count" }
}
}
]);
I have a sample collection containing users and their departments
db.user.insertMany([
{
"department":"IT",
"firstName":{
"en":"Frodo",
"ru":"Фродо"
},
"lastName":{
"en":"Baggins",
"ru":"Беггинс"
}
},
{
"department":"IT",
"firstName":{
"en":"Bilbo",
"ru":"Билбо"
},
"lastName":{
"en":"Baggins",
"ru":"Беггинс"
}
},
{
"department":"Marketing",
"firstName":{
"en":"Merry",
"ru":"Мери"
},
"lastName":{
"en":"Brandybuck",
"ru":"Брендибак"
}
},
{
"department":"Marketing",
"firstName":{
"en":"Pippin",
"ru":"Пипин"
},
"lastName":{
"en":"Took",
"ru":"Тук"
}
}
])
Now what I want to do, is to query them grouped by the department, and apply localization.
So the desired output is
{
"IT":[
{
"_id":"5e808532ed036001cb7fe366",
"firstName":"Frodo",
"lastName":"Baggins"
},
{
"_id":"5e808532ed036001cb7fe367",
"firstName":"Bilbo",
"lastName":"Baggins"
}
],
"Marketing":[
{
"_id":"5e808532ed036001cb7fe368",
"firstName":"Merry",
"lastName":"Brandybuck"
},
{
"_id":"5e808532ed036001cb7fe369",
"firstName":"Pippin",
"lastName":"Took"
}
]
}
I have the following query which applies localization
db.user.aggregate([
{
$project: {
_id: '$_id',
firstName: '$firstName.en',
lastName: '$lastName.en'
}
}
]).pretty()
I looked through the $group documentation, but it seems to require an aggregate function, which is not what I need. How should I group the data?
You have to use $group.
db.collection.aggregate([
{
$group: {
_id: "$department",
data: {
$push: {
_id: "$_id",
firstName: "$firstName",
lastName: "$lastName"
}
}
}
},
{
$group: {
_id: null,
data: {
$push: {
k: "$_id",
v: "$data"
}
}
}
},
{
$replaceRoot: {
newRoot: {
$arrayToObject: "$data"
}
}
}
])
Playground
I have documents in mongodb like this
{
_id: "5cfed55974c7c52ecc33ada8",
name: "Garona",
realm: "Blackrock",
faction: "Horde",
race: "Orc",
class: "Rogue",
guild: "",
level: 33,
lastSeen: "2019-06-10T00:00:00.000Z",
__v: 0
},
{
_id: "5cfed55974c7c52ecc33ade8",
name: "Muradin",
realm: "Alleria",
faction: "Alliance",
race: "Dwarf",
class: "Warrior",
guild: "Stormstout Brewing Co",
level: 42,
lastSeen: "2019-06-11T00:00:00.000Z",
__v: 0
}
What I'm trying to do, is to group by a fields and get a sum of it. So far I figured it out to do it for one field at once like so
{
$group: {
_id: {
classes: '1',
class: '$class'
},
total: { $sum: 1 }
}
},
{
$group: {
_id: '$_id.classes',
total: { $sum: '$total' },
classes: {
$push: {
class: '$_id.class',
total: '$total'
}
}
}
}
Which produces something like this
{
_id: "1",
total: 40,
classes: [
{
class: "Warrior",
total: 17
},
{
class: "Rogue",
total: 23
}
}
But I want to do it for more than one field at once, so that I can get an output like this.
{
_id: "1",
total: 40,
classes: [
{
class: "Warrior",
total: 17
},
{
class: "Rogue",
total: 23
},
factions: [
{
faction: "Alliance",
total: 27
},
{
faction: "Horde",
total: 13
}
}
No I'm wondering if it is even possible to do it in one query in an easy way or if I would be better to do a seperate query for each field.
You can do this by using the $facet aggregation stage
Processes multiple aggregation pipelines within a single stage on the same set of input documents. Each sub-pipeline has its own field in the output document where its results are stored as an array of documents.
I only slightly modified your original pipeline, and then just copied it for the 'factions' field.
The last 3 stages in my solution aren't really necessary, they just clean up the output a little bit.
You can probably take it from here, good luck.
db.collection.aggregate([
{
"$facet": {
"classes": [
{
$group: {
_id: "$class",
total: {
$sum: 1
}
}
},
{
$group: {
_id: null,
total: {
$sum: "$total"
},
"classes": {
$push: {
class: "$_id",
total: "$total"
}
}
}
}
],
"factions": [
{
$group: {
_id: "$faction",
total: {
$sum: 1
}
}
},
{
$group: {
_id: null,
total: {
$sum: "$total"
},
"factions": {
$push: {
faction: "$_id",
total: "$total"
}
}
}
}
]
}
},
{
$unwind: "$classes"
},
{
$unwind: "$factions"
},
{
$project: {
"classes._id": 0,
"factions._id": 0
}
}
])
Output
[
{
"classes": {
"classes": [
{
"class": "Warrior",
"total": 1
},
{
"class": "Rogue",
"total": 1
}
],
"total": 2
},
"factions": {
"factions": [
{
"faction": "Alliance",
"total": 1
},
{
"faction": "Horde",
"total": 1
}
],
"total": 2
}
}
]