How do we find keys which do not exist in collection.
Given an input list of keys ['3321', '2121', '5647'] , i want to return those that do not exist in the collection :
{ "_id" : { "$oid" : "5e2993b61886a22f400ea319" }, "scrip" : "5647" }
{ "_id" : { "$oid" : "5e2993b61886a22f400ea31a" }, "scrip" : "3553" }
So the expected output is ['3321', '2121']
This aggregation gets the desired output (works with MongoDB version 3.4 or later):
INPUT_ARRAY = ['3321', '2121', '5647']
db.test.aggregate( [
{
$match: {
scrip: {
$in: INPUT_ARRAY
}
}
},
{
$group: {
_id: null,
matches: { $push: "$scrip" }
}
},
{
$project: {
scrips_not_exist: { $setDifference: [ INPUT_ARRAY, "$matches" ] },
_id: 0
}
}
] )
The output:
{ "scrips_not_exist" : [ "3321", "2121" ] }
Related
Given the following document data in collection called 'blah'...
[
{
"_id" : ObjectId("60913f55987438922d5f0db6"),
"procedureCode" : "code1",
"description" : "Description 1",
"coding" : [
{
"system" : "ABC",
"code" : "L111"
},
{
"system" : "DEFG",
"code" : "S222"
}
]
},
{
"_id" : ObjectId("60913f55987438922d5f0dbc"),
"procedureCode" : "code2",
"description" : "Description 2",
"coding" : [
{
"system" : "ABC",
"code" : "L999"
},
{
"system" : "DEFG",
"code" : "X3333"
}
]
}
]
What I want to get is all of the coding elements where system is ABC for all parents, and an array of codes like so.
[
{ "code": "L111" },
{ "code": "L999" },
]
If I use db.getCollection('blah').find({"coding.system": "ABC"}) I get the parent document with any child in the coding array of ICD.
If I use...
db.getCollection("blah")
.find({ "coding.system": "ABC" })
.projection({ "coding.code": 1 })
I do get the parent documents which have a child with a system of "ABC", but the coding for "DEFG" seems to come along for the ride too.
{
"_id" : ObjectId("60913f55987438922d5f0db6"),
"coding" : [
{
"code" : "L989"
},
{
"code" : "S102"
}
]
},
{
"_id" : ObjectId("60913f55987438922d5f0dbc"),
"coding" : [
{
"code" : "L989"
},
{
"code" : "X382"
}
]
}
I have also tried experimenting with:
db.getCollection("blah").aggregate(
{ $unwind: "$coding" },
{ $match: { "system": "ICD" } }
);
.. as per this page: mongoDB query to find the document in nested array
... but go no where fast with that approach. i.e. no records at all.
What query do I need, please, to achieve something like this..?
[
{ "code": "L111" },
{ "code": "L999" },
...
]
or even better, this..?
[
"L111",
"L999",
...
]
db.collection.aggregate([
{
$match: { "coding.system": "ABC" }
},
{
$unwind: "$coding"
},
{
$match: { "coding.system": "ABC" }
},
{
$project: { code: "$coding.code" }
}
])
mongoplayground
db.collection.aggregate([
{
$match: { "coding.system": "ABC" }
},
{
$unwind: "$coding"
},
{
$match: { "coding.system": "ABC" }
},
{
$group: {
_id: null,
coding: { $push: "$coding.code" }
}
}
])
mongoplayground
Instead of $unwind, $match you can also use $filter:
db.collection.aggregate([
{ $match: { "coding.system": "ABC" } },
{
$project: {
coding: {
$filter: {
input: "$coding",
cond: { $eq: [ "$$this.system", "ABC" ] }
}
}
}
}
])
I'm new to aggregation queries in Mongo and been really struggling trying to produce the output I want. I have the following aggregation query:
db.events.aggregate([
{ $match: { requestState: "APPROVED" } },
{ $unwind: { path: "$payload.description" } },
{ $group: { _id: { instr: "$payload.description", bu: "$createdByUser", count: { $sum: 1 } } } }
]);
that returns the following results:
{ "_id" : { "instr" : "ABC-123", "bu" : "BU2", "count" : 1 } }
{ "_id" : { "instr" : "ABC-123", "bu" : "BU1", "count" : 1 } }
{ "_id" : { "instr" : "DEF-456", "bu" : "BU1", "count" : 1 } }
How can I amend the aggregation query so that there are only 2 documents returned instead of 3? With the two "ABC-123" results combined into a single result with a new array of counts with the "bu" and "count" fields i.e.
{ "_id" : { "instr" : "ABC-123", "counts": [ { "bu" : "BU1", "count" : 1 }, { "bu" : "BU2", "count" : 1 } ] } }
Many thanks
You can add another stage to only $group by _id.instr and another stage to $project to your desired output shape
db.events.aggregate([
{
$match: { requestState: "APPROVED" }
},
{
$unwind: { path: "$payload.description" }
},
{
$group: {
_id: { instr: "$payload.description", bu: "$createdByUser", count: { $sum: 1 } }
}
},
{
$group: {
_id: { instr: "$_id.instr" },
counts: { $push: { bu: "$_id.bu", count: "$_id.count" } }
}
},
{
$project: {
_id: { instr: "$_id.instr", counts: "$counts" }
}
}
]);
I've tried many answers to similar problems using $lookup, $unwind, and $match, but I can't get this to work for my sub-sub-subdocument situation.
I have this collection, Things:
{
"_id" : ObjectId("5a7241f7912cfc256468cb27"),
"name" : "Fortress of Solitude",
"alias" : "fortress_of_solitude",
},
{
"_id" : ObjectId("5a7247ec548c9ad042f579e2"),
"name" : "Batcave",
"alias" : "batcave",
},
{
"_id" : ObjectId("6a7247bc548c9ad042f579e8"),
"name" : "Oz",
"alias" : "oz",
},
and this one-document collection, Venues:
{
"_id" : ObjectId("5b9acabbbf71f39223f8de6e"),
"name" : "The Office",
"floors" : [
{
"name" : "1st Floor",
"places" : [
{
"name" : "Front Entrance",
"alias" : "front_entrance"
}
]
},
{
"name" : "2nd Floor",
"places" : [
{
"name" : "Batcave",
"alias" : "batcave"
},
{
"name" : "Oz",
"alias" : "oz"
}
]
}
]
}
I want to return all the Things, but with the Venue's floors.places.name aggregated with each Thing if it exists if the aliases match between Things and Venues. So, I want to return:
{
"_id" : ObjectId("5a7241f7912cfc256468cb27"),
"name" : "Fortress of Solitude",
"alias" : "fortress_of_solitude",
<-- nothing added here because
<-- it's not found in Venues
},
{
"_id" : ObjectId("5a7247ec548c9ad042f579e2"),
"name" : "Batcave",
"alias" : "batcave",
"floors" : [ <-- this should be
{ <-- returned
"places" : [ <-- because
{ <-- the alias
name" : "Batcave" <-- matches
} <-- in Venues
] <--
} <--
] <--
},
{
"_id" : ObjectId("6a7247bc548c9ad042f579e8"),
"name" : "Oz",
"alias" : "oz",
"floors" : [ <-- this should be
{ <-- returned
"places" : [ <-- because
{ <-- the alias
name" : "Oz" <-- matches
} <-- in Venues
] <--
} <--
] <--
}
I've gotten as far as the following query, but it only returns the entire Venues.floors array as an aggregate onto each Thing, which is way too much extraneous data aggregated. I just want to merge each relevant floor.place sub-subsubdocument from Venues into its corresponding Thing if it exists in Venues.
db.getCollection('things').aggregate([
{$lookup: {from: "venues",localField: "alias",foreignField: "floors.places.alias",as: "matches"}},
{
$replaceRoot: { newRoot: { $mergeObjects: [ { $arrayElemAt: [ "$matches", 0 ] }, "$$ROOT" ] } }
},
{ $project: { matches: 0 } }
])
I'm struggling with existing answers, which seem to change at MongoDB version 3.2, 3.4, 3.6, or 4.2 to include or not include $unwind, $pipeline, and other terms. Can someone explain how to get a sub-sub-subdocument aggregated like this? Thanks!
You can try this :
db.things.aggregate([
{
$lookup:
{
from: "venues",
let: { alias: "$alias" },
pipeline: [
{ $unwind: { path: "$floors", preserveNullAndEmptyArrays: true } },
{ $match: { $expr: { $in: ['$$alias', '$floors.places.alias'] } } },
/** Below stages are only if you've docs like doc 2 in Venues */
{ $addFields: { 'floors.places': { $filter: { input: '$floors.places', cond: { $eq: ['$$this.alias', '$$alias'] } } } } },
{ $group: { _id: '$_id', name: { $first: '$name' }, floors: { $push: '$floors' } } },
{$project : {'floors.places.alias': 1, _id :0}} // Optional
],
as: "matches"
}
}
])
Test : MongoDB-Playground
Since MongoDB v3.6, we may perform uncorrelated sub-queries which gives us more flexibility to join two collections.
Try this:
db.things.aggregate([
{
$lookup: {
from: "venues",
let: {
"alias": "$alias"
},
pipeline: [
{
$unwind: "$floors"
},
{
$project: {
_id: 0,
places: {
$filter: {
input: "$floors.places",
cond: {
$eq: [
"$$alias",
"$$this.alias"
]
}
}
}
}
},
{
$match: {
"places.0": {
$exists: true
}
}
},
{
$unset: "places.name"
}
],
as: "floors"
}
}
])
MongoPlayground
I have the a collection of documents as follows an example document:
{
'publicacao' : { 'data': '2013-13-13', 'hora': '13:13:13'},
'conteudo' : 'https://docs.google.com/document/d/1EQynJTiBa6FNI2O8XfoV0clMPxS5uOAu0_jKyEwsTBE/edit?usp=sharing',
'titulo' : 'As histórias de ciclano',
'categoria' : 'Romance',
'autor' : 'Ciclano',
'avaliacoes': [
{
'leitor': 'Fulano',
'nota': 1
},
{
'leitor': 'Beltrano',
'nota': 0
}
],
'denuncias': [
{
'denunciante': 'Ciclano'
},
{
'denunciante': 'Beltrano'
}
]
}
then i made an aggregate to define some documents to be removed:
var cursor = db.livro.aggregate( [
{
$project: {
id:1,
remover: {
$gt: [
{ $size: "$denuncias" },
{
$divide: [
{ $size: "$avaliacoes" },
2
]
}
]
}
}
}
]);
this aggregation returns the following docs:
{ "_id" : ObjectId("5cf5a9be7d48c53504974439"), "remover" : false }
{ "_id" : ObjectId("5cf5a9be7d48c5350497443a"), "remover" : false }
{ "_id" : ObjectId("5cf5a9be7d48c5350497443b"), "remover" : true }
{ "_id" : ObjectId("5cfd746e40d53565ca52132b"), "remover" : false }
{ "_id" : ObjectId("5cfd746e40d53565ca52132c"), "remover" : false }
{ "_id" : ObjectId("5cfd746e40d53565ca52132d"), "remover" : true }
I need to remove all docs with "remove": true.
I don't know how to get those ones!
Resolved:
I used the cursor.forEach() to iterate the objects and find the objects with remove = true.
cursor.forEach(function (doc){
if(doc.remover == true) {
db.livro.remove({"_id": doc._id});
print("Doc removido: "+ doc._id)
}
});
Instead of doing this with code after the query it is better overall to do it in the actual aggregation. Just check with a $match if the array has an element:
db.collection.aggregate([
{
$match: {
"denuncias.0": {
$exists: true
}
}
},
{
$project: {
id: 1,
remover: {
$gt: [
{
$size: "$denuncias"
},
{
$divide: [
{
$size: "$avaliacoes"
},
2
]
}
]
}
}
}
])
You can see if working here
I have documents like this:
{
"_id" : ObjectId("5b3ced158735f1196d73a743"),
"cid" : 1,
"foo" : [
{
"k" : "sport",
"v" : "climbing"
},
{
"k" : "sport",
"v" : "soccer"
},
{
"k" : "sport",
"v" : "soccer"
}
]
}
This Query just return the documents which contains a soccer field.
db.coll.find({foo:{$elemMatch:{ v: "soccer"}} }, {"foo.$" : 1,cid:1})
returns:
{ "_id" : ObjectId("5b3ced158735f1196d73a743"), "cid" : 1, "node" : [ { "k" : "sport", "v" : "climbing" } ] }
But I want to know, how many soccer-Elements are in each returned document. How can I count them?
db.coll.aggregate(
// Pipeline
[
// Stage 1
{
$match: {
foo: {
$elemMatch: {
v: 'soccer'
}
}
}
},
// Stage 2
{
$unwind: {
path: '$foo'
}
},
// Stage 3
{
$project: {
cid: 1,
count: {
$cond: {
if: {
$eq: ['$foo.v', 'soccer']
},
then: {
$sum: 1
},
else: 0
}
}
}
},
// Stage 4
{
$group: {
_id: '$cid',
total_count: {
$sum: '$count'
}
}
}
]
);
You can use below query to $filter and $size the filtered array to count no of matching occurrences.
db.coll.aggregate([
{"$project":{
"cid":1,
"count":{
"$size":{
"$filter":{
"input":"$foo",
"cond":{"$eq":["$$this.v","soccer"]
}
}
}
}
}}
])