How can I return all objects from a collection where name is same in all objects?
For example in this case name: John
[
{
_id: 1,
name: "John",
last: "Smith"
},
{
_id: 8,
name: "John",
last: "Snow"
},
{
_id: 16,
name: "John",
last: "McKay"
},
]
you can use group in aggregate to return all data that have the same name
db.collection.aggregate([
{
"$group": {
"_id": "$name",
"orig": {
"$push": "$$ROOT"
}
}
},
{
"$addFields": {
"sizeOrig": {
$size: "$orig"
}
}
},
{
"$match": {
sizeOrig: {
$gt: 0
}
}
},
{
$unwind: "$orig"
},
{
"$replaceRoot": {
"newRoot": "$orig"
}
}
])
example : https://mongoplayground.net/p/DfTA6_pUaRA
but if you want just single data for each duplication , you need just do it by group
db.collection.aggregate([
{
"$group": {
"_id": "$name",
"orig": {
"$push": "$$ROOT"
}
}
}
])
https://mongoplayground.net/p/hd1z77cdtp0
you need to use "findAll({})" or just "find({})" with the collection name it will return an array object that will contain all the documents from the collection. For example if you have a collection or a model which is named "Employees" you need to do the following after connection to db.
Employees.find({});
This will return an array with all docs inside Employee collection. Once you have this returned you can iterate over it.
Related
I have the current aggregation output as follows:
[
{
"courseCount": 14
},
{
"registeredStudentsCount": 1
}
]
The array has two documents. I would like to combine all the documents into a single document having all the fields in mongoDB
db.collection.aggregate([
{
$group: {
_id: 0,
merged: {
$push: "$$ROOT"
}
}
},
{
$replaceRoot: {
newRoot: {
"$mergeObjects": "$merged"
}
}
}
])
Explained:
Group the output documents in one field with push
Replace the document root with the merged objects
Plyaground
{
$group: {
"_id": "null",
data: {
$push: "$$ROOT"
}
}
}
When you add this as the last pipeline, it will put all the docs under data, but here data would be an array of objects.
In your case it would be
{ "data":[
{
"courseCount": 14
},
{
"registeredStudentsCount": 1
}
] }
Another approach would be,
db.collection.aggregate([
{
$group: {
"_id": "null",
f: {
$first: "$$ROOT",
},
l: {
$last: "$$ROOT"
}
}
},
{
"$project": {
"output": {
"courseCount": "$f.courseCount",
"registeredStudentsCount": "$l.registeredStudentsCount"
},
"_id": 0
}
}
])
It's not dynamic as first one. As you have two docs, you can use this approach. It outputs
[
{
"output": {
"courseCount": 14,
"registeredStudentsCount": 1
}
}
]
With extra pipeline in the second approach
{
"$replaceRoot": {
"newRoot": "$output"
}
}
You will get the output as
[
{
"courseCount": 14,
"registeredStudentsCount": 1
}
]
I want to print grouped by date and by "productId" within the date. In this example, the output should be as follow:
[
{
"_id": "2018-03-04",
"product1": 2,
"product2": 2
}
]
Data: https://mongoplayground.net/p/gzvm11EIPn2
How to make it?
When you use the $group stage in aggregation you learn to group by one field as such: { $group: { "_id": "$field1"...
When you want to group by two or more fields "_id" needs to be a subdocument and you pass the fields as key value pairs inside the subdocument as such:
db.mycollection.aggregate([
{
$group:
{
"_id": { "product1": "$product1", "product2": "$product2", ... }
}
}
])
... etc.
$group - Group by createdAt (date string) and productId and perform count via $sum.
$group - Group by createdAtand push data from (1) to products array field.
$replaceRoot - Replace input document with new document.
3.1. $arrayToObject - Convert the object from products array field to key value pair with productId (key) and count (value).
3.2. $mergeObjects - Create object with _id and merge the object from (3.2) into 1 object.
db.collection.aggregate([
{
$group: {
_id: {
createdAt: {
$dateToString: {
format: "%Y-%m-%d",
date: "$createdAt"
}
},
productId: "$productId"
},
count: {
$sum: 1
}
}
},
{
$group: {
_id: "$_id.createdAt",
products: {
$push: {
productId: "$_id.productId",
count: "$count"
}
}
}
},
{
"$replaceRoot": {
"newRoot": {
"$mergeObjects": [
{
_id: "$_id"
},
{
$arrayToObject: {
$map: {
input: "$products",
in: {
k: {
$toString: "$$this.productId"
},
v: "$$this.count"
}
}
}
}
]
}
}
}
])
Sample Mongo Playground
Output
[
{
"5e345223b3aa703b8a9a4f34": 2,
"5e345223b3aa703b8a9a4f35": 2,
"_id": "2018-03-04"
}
]
I have a MongoDB document like this:
[
{
"_id": {
"$oid": "5ff09030cd55d6d9f378d460"
},
"username": "a value",
"userid": "123456",
"last_access_ts": 1612426253,
"last_access": "2021-2-4 9:10:53",
"anotherid": 12345678910,
"verified_date": "2021-1-2 16:24:32",
"verified_ts": 1609601072,
"group_users": {
"-1001159747589": [
{
"anotherid": 12345678910,
"userid": "123456"
}
],
"-1001143137644": [
{
"anotherid": 12345678910,
"userid": "123456"
}
],
"-1001368608972": [
{
"anotherid": 12345678910,
"userid": "123456"
}
]
},
"registered_access": "2021-1-2 16:24:42",
}
]
I've two questions.
First one: I need to count the elements inside each group_users[key] object, and I'm stuck with this aggregate:
db.collection.aggregate([
{
$match: {
username: "a value"
}
},
{
$project: {
_id: 1,
userid: 1,
"groups": {
"$objectToArray": "$group_users"
}
}
},
{
$unwind: "$groups",
},
])
This aggregate gives me this result:
[
{
"_id": ObjectId("5ff09030cd55d6d9f378d460"),
"groups": {
"k": "-1001449720492",
"v": [
{
"anotherid": 12345678910,
"userid": "123456"
}
]
},
"userid": "123456"
},
{
"_id": ObjectId("5ff09030cd55d6d9f378d460"),
"groups": {
"k": "-1001159747589",
"v": [
{
"anotherid": 12345678910,
"userid": "123456"
}
]
},
"userid": "123456"
},
{
"_id": ObjectId("5ff09030cd55d6d9f378d460"),
"groups": {
"k": "-1001143137644",
"v": [
{
"anotherid": 12345678910,
"userid": "123456"
}
]
},
"userid": "123456"
}
]
How can I count each single groups[v] and then re-group the data? I would like to have a result like:
{
... some user data
"groups": {
"group_key": "count",
"second_group_key": "count",
"third_group_key": "count"
}
}
Is it possible with aggregate or I need to loop in the code?
My second question is always about the group_users. Is possible to have, recursively, the user data inside a group_users object?
I mean, every object inside group_users is an array of users; from this array can I have the user data (maybe with $graphLookup?) using the userid field or the anotherid field?
As a result from this second aggregate I would like to have something like this:
{
... some user data
"groups": {
"group_key": [{"userid": userid, "username": username}],
"second_group_key": [{"userid": userid, "username": username}],
"third_group_key": [{"userid": userid, "username": username}]
}
}
Obviously I can limit this "recursion" to 10 elements per time.
Thanks for any advice.
$objectToArray convert group_users object to array
$let to Bind variable group_arr for use in the specified expression, and returns the result of the expression.
$map to iterate loop of bind variable group_arr, get size of total element of v and return k and v,
$arrayToObject convert returned array from $map to object
db.collection.aggregate([
{ $match: { username: "a value" } },
{
$project: {
_id: 1,
userid: 1,
groups: {
$let: {
vars: { group_arr: { $objectToArray: "$group_users" } },
in: {
$arrayToObject: {
$map: {
input: "$$group_arr",
in: {
k: "$$this.k",
v: { $size: "$$this.v" }
}
}
}
}
}
}
}
}
])
Playground
Second question,
$unwind deconstruct groups array
$lookup with pipeline, match anotherid $in condition and return required fields
$group by _id and reconstruct groups array
$arrayToObject convert groups array to object
db.collection.aggregate([
{ $match: { username: "a value" } },
{
$project: {
_id: 1,
userid: 1,
groups: { $objectToArray: "$group_users" }
}
},
{ $unwind: "$groups" },
{
$lookup: {
from: "collection",
let: { anotherid: "$groups.v.anotherid" },
pipeline: [
{ $match: { $expr: { $in: ["$anotherid", "$$anotherid"] } } },
{
$project: {
_id: 0,
userid: 1,
username: 1
}
}
],
as: "groups.v"
}
},
{
$group: {
_id: "$_id",
groups: { $push: "$groups" },
userid: { $first: "$userid" }
}
},
{ $addFields: { groups: { $arrayToObject: "$groups" } } }
])
Playground
I am creating a mongo aggregate pipeline where I unwind a document by a field (doors) that is a list. Then, I filter by a condition on a property in the individual door.
How would I combine the filtered results back together such that the result is in its original form?
Here is an example of a document in my collection:
{ "uuid": "00000000-0000-0000-0000-000000000000",
"name": "Building1",
"doors": [
{
"doorUuid": "11111111-1111-1111-1111-111111111111",
"creationTime": null
},
{
"doorUuid": "22222222-2222-2222-2222-222222222222",
"creationTime": 1560194908942
},
{
"doorUuid": "33333333-3333-3333-3333-333333333333",
"creationTime": 1560195008942
}
]
}
For example, if I wanted to filter out all doors with null creationTime's, the output I want would have the same structure above but with only two doors.
$group with $push:
MongoPlayground
db.collection.aggregate([
{
$unwind: "$doors"
},
{
$match: {
"doors.creationTime": {
$ne: null
}
}
},
{
$group: {
_id: "$_id",
name: {
$last: "$name"
},
uuid: {
$last: "$uuid"
},
doors: {
$push: "$doors"
}
}
}
])
This is the data I have in my mongo db:
{
"_id": ObjectId("556d1c7716efd4a035d8e473"),
"products": [
{
"gtin": 77770000222313,
"gpc": 10000068
},
{
"gtin": 77770000222312,
"gpc": 10000068
}
]
}
How do I aggregate this so that I get gpc value and then an array under that of the gtins? Something like:
{
"gpc":10000068,
"gtin":[77770000222312,77770000222313]
}
Use aggregation framework
db.collection.aggregate(
[
{ $unwind: "$products" },
{ $group: { _id: "$products.gpc", gtin: { $push: "$products.gtin" }}},
{ $project: { gpc: "$_id", gtin: 1, _id: 0 }}
]
)