I've nested JSON like this. I want to retrieve the value of "_value" in second level. i,e. "Living Organisms" This is my JSON document.
{
"name": "Biology Book",
"data": {
"toc": {
"_version": "1",
"ge": [
{
"_name": "The Fundamental Unit of Life",
"_id": "5a",
"ge": [
{
"_value": "Living Organisms",
"_id": "5b"
}
]
}
]
}
}
}
This is what I've tried, using the "_id", I want to retrieve it's "_value"
db.products.aggregate([{"$match":{ "data.toc.ge.ge._id": "5b"}}])
This is the closest I could get to the output you mentioned in the comment above. Hope it helps.
db.collection.aggregate([
{
$match: {
"data.toc.ge.ge._id": "5b"
}
},
{
$unwind: "$data.toc.ge"
},
{
$unwind: "$data.toc.ge.ge"
},
{
$group: {
_id: null,
book: {
$push: "$data.toc.ge.ge._value"
}
}
},
{
$project: {
_id: 0,
first: {
$arrayElemAt: [
"$book",
0
]
},
}
}
])
Output:
[
{
"first": "Living Organisms"
}
]
You can check what I tried here
If you are using Mongoid:
(1..6).inject(Model.where('data.toc.ge.ge._id' => '5b').pluck('data.toc.ge.ge._value').first) { |v| v.values.first rescue v.first rescue v }
# => "Living Organisms"
6 is the number of containers to trim from the output (4 hashes and 2 arrays).
If I understand your question correctly, you only care about _value, so it sounds like you might want to use a projection:
db.products.aggregate([{"$match":{ "data.toc.ge.ge._id": "5b"}}, { "$project": {"data.toc.ge.ge._value": 1}}])
Related
i have a collection with more then 1000 documents and there are some documents with same value in some fields, i need to get those
the collection is:
[{_id,fields1,fields2,fields3,etc...}]
what query can i use to get all the elements that have the same 3 fields for example:
[
{_id:1,fields1:'a',fields2:1,fields3:'z'},
{_id:2,fields1:'a',fields2:1,fields3:'z'},
{_id:3,fields1:'f',fields2:2,fields3:'g'},
{_id:4,fields1:'f',fields2:2,fields3:'g'},
{_id:5,fields1:'j',fields2:3,fields3:'g'},
]
i need to get
[
{_id:2,fields1:'a',fields2:1,fields3:'z'},
{_id:4,fields1:'f',fields2:2,fields3:'g'},
]
in this way i can easly get a list of "duplicate" that i can delete if needed, it's not really important get id 2 and 4 or 1 and 3
but 5 would never be included as it's not 'duplicated'
EDIT:
sorry but i forgot to mention that there are some document with null value i need to exclude those
This is the perfect use case of window field. You can use $setWindowFields to compute $rank in the grouping/partition you want. Then, get those rank not equal to 1 to get the duplicates.
db.collection.aggregate([
{
$match: {
fields1: {
$ne: null
},
fields2: {
$ne: null
},
fields3: {
$ne: null
}
}
},
{
"$setWindowFields": {
"partitionBy": {
fields1: "$fields1",
fields2: "$fields2",
fields3: "$fields3"
},
"sortBy": {
"_id": 1
},
"output": {
"duplicateRank": {
"$rank": {}
}
}
}
},
{
$match: {
duplicateRank: {
$ne: 1
}
}
},
{
$unset: "duplicateRank"
}
])
Mongo Playground
I think you can try this aggregation query:
First group by the feilds you want to know if there are multiple values.
It creates an array with the _ids that are repeated.
Then get only where there is more than one ($match).
And last project to get the desired output. I've used the first _id found.
db.collection.aggregate([
{
"$group": {
"_id": {
"fields1": "$fields1",
"fields2": "$fields2",
"fields3": "$fields3"
},
"duplicatesIds": {
"$push": "$_id"
}
}
},
{
"$match": {
"$expr": {
"$gt": [
{
"$size": "$duplicatesIds"
},
1
]
}
}
},
{
"$project": {
"_id": {
"$arrayElemAt": [
"$duplicatesIds",
0
]
},
"fields1": "$_id.fields1",
"fields2": "$_id.fields3",
"fields3": "$_id.fields2"
}
}
])
Example here
I have two collections userProfile and skills,
Eg:userProfile
{
"_id": "5f72c6d4e23732390c96b031",
"name":"name"
"other_skills": [
"1","2"
],
"primary_skills": [
{
"_id": "607ffd1549e13876fef7f2c5",
"years": 4.5,
"skill_id": "1"
},
{
"_id": "607ffd1549e13876fef7f2c6",
"years": 2,
"skill_id": "2"
},
{
"_id": "607ffd1549e13876fef7f2c7",
"years": 1,
"skill_id": "3"
}
]
}
Eg:Skills
{
"_id":1,
"name": "Ruby on Rails",
}
{
"_id":2,
"name": "PHP",
}
{
"_id":3,
"name": "php",
}
I want to retrieve the userprofile based on the skills
eg: input of skill php i want to retrieve the userprofiles that matches either in primary_skills or other_skills
But I got confused about the implementation, I think it can do with pipeline in lookup and the elemMatch. This is the query I tried so far
const skills = ['php','PHP']
userProfile.aggrigate([{
$lookup:{
from:'skills',
let:{'primary_skills':'$primary_skills'},
pipeline:[
{
$match:{
primary_skills:{
$elemMatch:{
name:'' //not sure how to write match
}
}
}
}
]
}
}])
Can somebody help me with this, Thanks in advance
I'll first show you how to correct your pipeline to work, however this approach is very inefficient as you will have to $lookup on every single user in your db which is obviously a lot of overhead.
Here is how to properly match your condition:
const skills = ['php','PHP']
db.userProfile.aggregate([
{
$lookup: {
from: "skills",
let: {
"primary_skills": {
$map: {
input: "$primary_skills",
as: "skill",
in: "$$skill.skill_id"
}
},
"other_skills": "$other_skills"
},
pipeline: [
{
$match: {
$expr: {
"$in": [
"$_id",
{
"$concatArrays": [
"$$other_skills",
"$$primary_skills"
]
}
]
}
}
}
],
as: "skills"
}
},
{
$match: {
'skills.name': {$in: skills}
}
}
])
Mongo Playground
As I've said I recommend you do not do this. what I suggest you do is split it into 2 calls, first fetch the relevant skill ids. and then query on users.
By doing this you can also utilize indexes for much faster queries, like so:
const skills = ['php', 'PHP'];
const matchedSkillIds = await skills.distinct('_id', {name: {$in: skills}});
const users = await userProfile.find({
$or: [
{
'primary_skills.skill_id': {$in: matchedSkillIds}
},
{
'other_skills': {$in: matchedSkillIds}
}
]
})
Finally if you do insist on doing it in one query at the very least start the pipeline from the skill collection.
I have the following mongo db schema and I am trying to build an aggregate query that searches under github_open_issues under the repo key and can return me a match for all the values with repoA as the value. I have tried the following as my query however its not returning any result. Im a bit confused why this is not working as I have another db with a schema similar to this and this type of query works there but here something seems to be different and is not working. I have also put together this interactive example mongoplayground
query
db.collection.aggregate([
{
"$unwind": "$github_open_issues"
},
{
"$match": {
"github_open_issues.repo": {
"$in": [
"repoA"
]
}
}
},
])
schema
[
{
"github_open_issues": {
"0": {
"git_url": "https://github.com/",
"git_assignees": "None",
"git_open_date": "2019-09-26",
"git_id": 253113,
"repo": "repoA",
"git_user": "userA",
"state": "open"
},
"1": {
"git_url": "https://github.com/",
"git_assignees": "None",
"git_open_date": "2019-11-15",
"git_id": 294398,
"repo": "repoB",
"git_user": "userB",
"state": "open"
},
"2": {
"git_url": "https://github.com/",
"git_assignees": "None",
"git_open_date": "2021-04-12",
"git_id": 661208,
"repo": "repoA",
"state": "open"
}
},
"unique_label_seen": {
"568": {
"label_name": "some label",
"times_seen": 12,
"535": {
"label_name": "another label",
"times_seen": 1
}
}
}
}
]
$objectToArray convert github_open_issues object to array in key-value format
$filter to iterate loop of above converted array and filter your search condition
$match to filter github_open_issues not empty
$arrayToObject convert github_open_issues array to object
db.collection.aggregate([
{
$addFields: {
github_open_issues: {
$filter: {
input: { $objectToArray: "$github_open_issues" },
cond: { $in: ["$$this.v.repo", ["repoA"]] }
}
}
}
},
{ $match: { github_open_issues: { $ne: [] } } },
{ $addFields: { github_open_issues: { $arrayToObject: "$github_open_issues" } } }
])
Playground
You query is correct but you data in schema placed wrong inside github_open_issues.repo your objects are place by numbers like {"0": {values... }, "1":{values... }} which cannot get your desired value. You can check the playground now playground
I have a table structured as follows:
db.l2vpn_fdb_database.findOne()
{
_id: ObjectId("5f5257f11324c04122714445"),
hostname: "spine01-drt-red",
l2vpn_fdb_database: {
MAC: [
{
IfIndex: "1631",
MacAddr: "00-00-0C-07-AC-01",
SrvID: "1",
VsiName: "EVPN",
},
{
IfIndex: "0",
MacAddr: "00-00-0C-07-AC-02",
SrvID: "0",
VsiName: "EVPN",
},
{
IfIndex: "1631",
MacAddr: "00-00-0C-07-AC-0A",
SrvID: "1",
VsiName: "EVPN",
},
],
},
}
I'd like to search for "MacAddr" object, could you help me figure out based on above? So essentially I'd like to be able to parse database for a MacAddress assuming it's there and be able to get "IfIndex" for further processing.
Thank you.
You can use $filter to get matched objects
db.collection.aggregate([
{
$project: {
l2vpn_fdb_database: {
$filter: {
input: "$l2vpn_fdb_database.MAC",
cond: {
$eq: [
"$$this.IfIndex",
"1631"
]
}
}
}
}
}
])
Working Mongo playground
for Hostname with macAddr try like this,
db.collection.aggregate([
{
$project: {
l2vpn_fdb_database: {
$filter: {
input: "$l2vpn_fdb_database.MAC",
cond: {
$eq: [
"$$this.IfIndex",
"1631"
]
}
}
},
hostname:{
$eq:['$hostname','spine01-drt-red']
}
}
}
])
This query could help you.
b.l2vpn_fdb_database.findOne({
"l2vpn_fdb_database.MAC.MacAddr": "00-00-0C-07-AC-01",
},
{
"l2vpn_fdb_database.MAC.$": 1
})
The result is the same document just with 1 element in the array
Result:
{
"_id": ObjectId("5f5257f11324c04122714445"),
"l2vpn_fdb_database": {
"MAC": [
{
"IfIndex": "1631",
"MacAddr": "00-00-0C-07-AC-01",
"SrvID": "1",
"VsiName": "EVPN"
}
]
}
}
I've a problem with a huge MongoDb aggregation pipeline. I've many constraint and I've simplified the problem a lot. Hence, don't discuss the goal for this query.
I've a mongo aggregation that gives something similar to this:
[
{
"content": {
"processes": [
{
"id": "101a",
"title": "delivery"
},
{
"id": "101b",
"title": "feedback"
}
]
}
}
]
To this intermediate result I'm forced to apply a project operation in order to obtain something similar to this:
[
{
"results":
{
"titles": [
{
"id": "101a",
"value": "delivery"
},
{
"id": "101b",
"value": "feedback"
}
]
}
}
]
enter code here
But applying this projections:
"results.titles.id": "$content.processes.id",
"results.titles.value": "$content.processes.title"
I obtain this:
[
{
"results":
{
"titles": {
"id": ["101a", "101b"]
"value": ["delivery", "feedback"]
}
}
}
}
]
Collection are created but not in the proper position.
Is it possible to exploit some operator inside the project operation in order to tell mongo to create an array in a parent position?
Something like this:
"results.titles.$[x].value" : "$content.processes.value"
You can use the dot notation to project entire array:
db.col.aggregate([
{
$project: {
"results.titles": "$content.processes"
}
}
])
and if you need to rename title to value then you have to apply $map operator:
db.col.aggregate([
{
$project: {
"results.titles": {
$map: {
input: "$content.processes",
as: "process",
in: {
id: "$$process.id",
value: "$$process.title"
}
}
}
}
}
])