I have a collection of documents that look like this
{
_id : 21353456,
product : "xy",
text : "asdf",
reviews : [
{
username : "User1",
userID: 12
text : "hi"
rate: 4,
},
{
username : "User2",
userID: 123
text : "hi1"
rate:2,
}
]
}
I want to retrieve the average rating for user1 on all the product they have rated.
db.collection.aggregate([{$unwind: "$reviews"},{$match: {"$review.userID": "12"}},{$group: { _id: "$reviews.userName",
{avgRate: {$avg: "$reviews.rate"}}})]
)
I tried this but I keep getting unexpected token errors for "," where the last ")" is.
You did this:
db.collection.aggregate([
{ $unwind: "$reviews" },
{ $match: { "$review.userID": "12" } },
{ $group: { _id: "$reviews.userName",
{ avgRate: { $avg: "$reviews.rate" } }})]
)
Must be this:
db.collection.aggregate([
{ $unwind: "$reviews" },
{ $match: { "$review.userID": "12" } },
{
$group: {
_id: "$reviews.userName",
avgRate: { $avg: "$reviews.rate" }
}
}
])
Related
I have a collection of 1000 documents like this:
{
"_id" : ObjectId("628b63d66a5951db6bb79905"),
"index" : 0,
"name" : "Aurelia Gonzales",
"isActive" : false,
"registered" : ISODate("2015-02-11T04:22:39.000+0000"),
"age" : 41,
"gender" : "female",
"eyeColor" : "green",
"favoriteFruit" : "banana",
"company" : {
"title" : "YURTURE",
"email" : "aureliagonzales#yurture.com",
"phone" : "+1 (940) 501-3963",
"location" : {
"country" : "USA",
"address" : "694 Hewes Street"
}
},
"tags" : [
"enim",
"id",
"velit",
"ad",
"consequat"
]
}
I want to group those by year and gender. Like In 2014 male registration 105 and female registration 131. And finally return documents like this:
{
_id:2014,
male:105,
female:131,
total:236
},
{
_id:2015,
male:136,
female:128,
total:264
}
I have tried till group by registered and gender like this:
db.persons.aggregate([
{ $group: { _id: { year: { $year: "$registered" }, gender: "$gender" }, total: { $sum: NumberInt(1) } } },
{ $sort: { "_id.year": 1,"_id.gender":1 } }
])
which is return document like this:
{
"_id" : {
"year" : 2014,
"gender" : "female"
},
"total" : 131
}
{
"_id" : {
"year" : 2014,
"gender" : "male"
},
"total" : 105
}
Please guide to figure out from this whole.
db.collection.aggregate([
{
"$group": { //Group things
"_id": "$_id.year",
"gender": {
"$addToSet": {
k: "$_id.gender",
v: "$total"
}
},
sum: { //Sum it
$sum: "$total"
}
}
},
{
"$project": {//Reshape it
g: {
"$arrayToObject": "$gender"
},
_id: 1,
sum: 1
}
},
{
"$project": { //Reshape it
_id: 1,
"g.female": 1,
"g.male": 1,
sum: 1
}
}
])
Play
Just add one more group stage to your aggregation pipeline, like this:
db.persons.aggregate([
{ $group: { _id: { year: { $year: "$registered" }, gender: "$gender" }, total: { $sum: NumberInt(1) } } },
{ $sort: { "_id.year": 1,"_id.gender":1 } },
{
$group: {
_id: "$_id.year",
male: {
$sum: {
$cond: {
if: {
$eq: [
"$_id.gender",
"male"
]
},
then: "$total",
else: 0
}
}
},
female: {
$sum: {
$cond: {
if: {
$eq: [
"$_id.gender",
"female"
]
},
then: "$total",
else: 0
}
}
},
total: {
$sum: "$total"
}
},
}
]);
Here's the working link. We are grouping by year in this last step, and calculating the counts for gender conditionally and the total is just the total of the counts irrespective of the gender.
Besides #Gibbs mentioned in the comment which proposes the solution with 2 $group stages,
You can achieve the result as below:
$group - Group by year of registered. Add gender value into genders array.
$sort - Order by _id.
$project - Decorate output documents.
3.1. male - Get the size of array from $filter the value of "male" in "genders" array.
3.2. female - Get the size of array from $filter the value of "female" in "genders" array.
3.3. total - Get the size of "genders" array.
Propose this method if you are expected to count and return the "male" and "female" gender fields.
db.collection.aggregate([
{
$group: {
_id: {
$year: "$registered"
},
genders: {
$push: "$gender"
}
}
},
{
$sort: {
"_id": 1
}
},
{
$project: {
_id: 1,
male: {
$size: {
$filter: {
input: "$genders",
cond: {
$eq: [
"$$this",
"male"
]
}
}
}
},
female: {
$size: {
$filter: {
input: "$genders",
cond: {
$eq: [
"$$this",
"female"
]
}
}
}
},
total: {
$size: "$genders"
}
}
}
])
Sample Mongo Playground
MongoDB version:4.2.17.
Trying out aggregation on data in a collection.
Example data:
{
"_id" : "244",
"pubName" : "p1",
"serviceIdRef" : "36e9c779-7865-4b74-a30b-e4d6a0cc5295",
"serviceName" : "my-service",
"subName" : "c1",
"pubState" : "INVITED"
}
I would like to:
Do a match by something (let’s say subName) and group by serviceIdRef and then limit to return X entries
Also return for each of the serviceIdRefs, the count of the documents in each of ACTIVE or INVITED states. And Y (for this example, say Y=3) documents that are in this state.
For example, the output would appear as (in brief):
[
{
serviceIdRef: "36e9c779-7865-4b74-a30b-e4d6a0cc5295",
serviceName:
state:[
{
pubState: "INVITED"
count: 200
sample: [ // Get those Y entries (here Y=3)
{
// sample1 like:
"_id" : "244",
"pubName" : "p1",
"serviceIdRef" : "36e9c779-7865-4b74-a30b-e4d6a0cc5295",
"serviceName" : "my-service",
"subName" : "c1",
"pubState" : "INVITED"
},
{
sample2
},
{
sample3
}
]
},
{
pubState: "ACTIVE", // For this state, repeat as we did for "INVITED" state above.
......
}
]
}
{
repeat for another service
}
]
So far I have written this but am not able to get those Y entries. Is there a (better) way?
This is what I have so far (not complete and not exactly outputs in the format above):
db.sub.aggregate(
[{
$match:
{
"subName": {
$in: ["c1", "c2"]
},
"$or": [
{
"pubState": "INVITED",
},
{
"pubState": "ACTIVE",
}
]
}
},
{
$group: {
_id: "$serviceIdRef",
subs: {
$push: "$$ROOT",
}
}
},
{
$sort: {
_id: -1,
}
},
{
$limit: 22
},
{
$facet:
{
facet1: [
{
$unwind: "$subs",
},
{
$group:
{
_id: {
"serviceName" : "$_id",
"pubState": "$subs.pubState",
"subState": "$subs.subsState"
},
count: {
$sum: 1
}
}
}
]
}
}
])
You have to do the second $group stage to manage nested structure,
$match your conditions
$sort by _id in descending order
$group by serviceIdRef and pubState, get first required fields and prepare the array for sample, and get count of documents
$group by only serviceIdRef and construct the state array
$slice for limit the document in sample
db.collection.aggregate([
{
$match: {
subName: { $in: ["c1", "c2"] },
pubState: { $in: ["INVITED", "ACTIVE"] }
}
},
{ $sort: { _id: -1 } },
{
$group: {
_id: {
serviceIdRef: "$serviceIdRef",
pubState: "$pubState"
},
serviceName: { $first: "$serviceName" },
sample: { $push: "$$ROOT" },
count: { $sum: 1 }
}
},
{
$group: {
_id: "$_id.serviceIdRef",
serviceName: { $first: "$serviceName" },
state: {
$push: {
pubState: "$_id.pubState",
count: "$count",
sample: { $slice: ["$sample", 22] }
}
}
}
}
])
Playground
I have a collection like this:
{
"_id" : ObjectId("5f4e81f1da5ea3cb7c248a8f"),
"type" : "TYPE_1",
"updateTime" : ISODate("2020-08-24T11:10:43.219+0000")
}
{
"_id" : ObjectId("5f4e8206da5ea3cb7c248a90"),
"type" : "TYPE_1",
"updateTime" : ISODate("2020-09-24T11:10:43.219+0000")
}
{
"_id" : ObjectId("5f4e821fda5ea3cb7c248a91"),
"type" : "TYPE_2",
"updateTime" : ISODate("2020-09-25T11:10:43.219+0000")
}
I want to know how many documents there are of each type and also obtain the date of the last global modification. For now I can get these results like this:
db.getCollection("test").aggregate(
// Pipeline
[
// Stage 1
{
$group: {
_id : "$type",
count: { $sum: 1 },
lastUpdate: { "$max": "$updateTime" }
}
},
// Stage 2
{
$sort: {
lastUpdate : -1
}
},
]
);
With which I get the results this way:
{
"_id" : "TYPE_2",
"count" : 1.0,
"lastUpdate" : ISODate("2020-09-25T11:10:43.219+0000")
}
{
"_id" : "TYPE_1",
"count" : 2.0,
"lastUpdate" : ISODate("2020-09-24T11:10:43.219+0000")
}
So I have both the sum of each document and the last modification (thanks to the sort).
But I would like to project and get the results like this, in a single result document:
{
"type1" : 2.0,
"type2" : 1.0,
"lastUpdate" : ISODate("2020-09-25T11:10:43.219+0000")
}
#varman's answer is good, this is just in different way,
$group you have already done by your self
$group create types array to combine all documents
$replaceWith to replace root with field types to convert $arrayToObject
db.collection.aggregate([
{
$group: {
_id: "$type",
count: { $sum: 1 },
lastUpdate: { $max: "$updateTime" }
}
},
{
$group: {
_id: null,
types: {
$push: {
k: "$_id",
v: "$count"
}
},
lastUpdate: { $max: "$lastUpdate" }
}
},
{
$replaceWith: {
$mergeObjects: [
{ lastUpdate: "$lastUpdate" },
{ $arrayToObject: "$types" }
]
}
}
])
Playground
You can use following stages after your stage.
{
$group: {
_id: null,
data: {
$push: {
type: "$_id",
count: "$count"
}
},
lastUpdate: {
$first: "$lastUpdate"
}
}
},
{
$project: {
data: {
$arrayToObject: {
$map: {
input: "$data",
in: {
k: "$$this.type",
v: "$$this.count"
}
}
}
},
lastUpdate: 1
}
},
{
$addFields: {
"data.lastUpdate": "$lastUpdate"
}
},
{
"$replaceRoot": {
"newRoot": "$data"
}
}
Working Mongo playground
I am trying the mongo rank calculation based on count and mentioned in below db schema. I am not getting the expecting results. Anyone help to resolve this?
Mongo Query:
db.company.aggregate([
{
"$group": {
"_id": {
"name1": "$name1",
"name2": "$name2",
},
"expanded": {
"$push": {
"name1": "$name1",
"name2": "$name2",
}
},
"count": { "$sum": 1 }
}
},
{ "$sort": { "count": -1 } },
{
$unwind: {
path: '$expanded',
includeArrayIndex: 'count'
}
}
]);
Expecting results like
Name|Count|Rank
Google|3|1
FB|2|2
Yahoo|1| 3
DB Schema :
{
"_id" : 1.0,
"name1" : "Yahoo",
"name2" : "Google",
"salary" : 1000.0
}
/* 2 */
{
"_id" : 2.0,
"name1" : "FB",
"name2" : "Google",
"salary" : 2000.0
}
/* 3 */
{
"_id" : 3.0,
"name1" : "Google",
"name2" : "FB",
"salary" : 1500.0
}
It seems like you should count name1 and name2 separately so you can create a temporary 2-element array and then run $unwind on that array. Additionally to get rank you have to $group by null to get single array of all groups, try:
db.collection.aggregate([
{
$project: {
key: [ "$name1", "$name2" ]
}
},
{
$unwind: "$key"
},
{
$group: {
_id: "$key",
count: { $sum: 1 }
}
},
{
$sort: {
count: -1
}
},
{
$group: {
_id: null,
groups: { $push: "$$ROOT" }
}
},
{
$unwind: {
path: '$groups',
includeArrayIndex: 'rank'
}
},
{
$project: {
_id: 0,
name: "$groups._id",
rank: { $add: [ "$rank", 1 ] },
count: "$groups.count"
}
}
])
Mongo Playground
try this
db.company.aggregate([
{
$group: {
_id:null,
names1: {$push: "$name1"},
names2: {$push:"$name2"},
}
},
{
$project: {
_id: 0,
names:{$concatArrays: ["$names1", "$names2"]}
}
},
{$unwind: "$names"},
{$sortByCount: "$names"},
{$addFields:{name: "$_id"}},
{
$group : {
_id: null,
records : { $push : {count : "$count", name : "$name"}}
}
},
{
$project: {
total_docs: {$size: "$records"},
records: 1
}
},
{$unwind: "$records"},
{
$project: {
_id: 0,
name: "$records.name",
count:"$records.count",
rank: {
$add:[
{
$subtract:["$total_docs", "$records.count"]
}, 1]
}
}
}])
I am trying to fetch all records (and count of all records) for a structure like the following,
{
id: 1,
level1: {
level2:
[
{
field1:value1;
},
{
field1:value1;
},
]
}
},
{
id: 2,
level1: {
level2:
[
{
field1:null;
},
{
field1:value1;
},
]
}
}
My requirement is to fetch the number of records that have field1 populated (atleast one in level2). I need to say fetch all the ids or the number of such ids.
The query I am using is,
db.table.find({},
{
_id = id,
value: {
$elemMatch: {'level1.level2.field1':{$exists: true}}
}
}
})
Please suggest.
EDIT1:
This is the question I was trying to ask in the comment. I was unable to elucidate in the comment properly. Hence, editing the question.
{
id: 1,
level1: {
level2:
[
{
field1:value1;
},
{
field1:value1;
},
]
}
},
{
id: 2,
level1: {
level2:
[
{
field1:value2;
},
{
field1:value2;
},
{
field1:value2;
}
]
}
}
{
id: 3,
level1: {
level2:
[
{
field1:value1;
},
{
field1:value1;
},
]
}
}
The query we used results in
value1: 4
value2: 3
I want something like
value1: 2 // Once each for documents 1 & 3
value2: 1 // Once for document 2
You can do that with the following find query:
db.table.find({ "level1.level2" : { $elemMatch: { field1 : {$exists: true} } } }, {})
This will return all documents that have a field1 in the "level1.level2" structure.
For your question in the comment, you can use the following aggregation to "I had to return a grouping (and the corresponding count) for the values in field1":
db.table.aggregate(
[
{
$unwind: "$level1.level2"
},
{
$match: { "level1.level2.field1" : { $exists: true } }
},
{
$group: {
_id : "$level1.level2.field1",
count : {$sum : 1}
}
}
]
UPDATE: For your question "'value1 - 2` At level2, for a document, assume all values will be the same for field1.".
I hope i understand your question correctly, instead of grouping only on the value of field1, i added the document _id as an xtra grouping:
db.table.aggregate(
[
{
$unwind: "$level1.level2"
},
{
$match: {
"level1.level2.field1" : { $exists: true }
}
},
{
$group: {
_id : { id : "$_id", field1: "$level1.level2.field1" },
count : {$sum : 1}
}
}
]
);
UPDATE2:
I altered the aggregation and added a extra grouping, the aggregation below gives you the results you want.
db.table.aggregate(
[
{
$unwind: "$level1.level2"
},
{
$match: {
"level1.level2.field1" : { $exists: true }
}
},
{
$group: {
_id : { id : "$_id", field1: "$level1.level2.field1" }
}
},
{
$group: {
_id : { id : "$_id.field1"},
count : { $sum : 1}
}
}
]
);