I have datas of following format collection(projects) inside my database:
{ "_id" : ObjectId("5981a80f223e491a58230e5d"), "id" : 2, "name" : "gbqplhlqxzwl", "managerId" : 65151, "startDate" : "03.11.1999", "finishDate" : "02.01.2003", "projectStatus" : "POSTPONED", "participants" : [ ], "estimatedBudget" : 6017891.811079914 }
{ "_id" : ObjectId("5981a80f223e491a58230e5e"), "id" : 3, "name" : "erfekfsdgryu", "managerId" : 83749, "startDate" : "07.07.2007", "finishDate" : "26.12.2027", "projectStatus" : "POSTPONED", "participants" : [ 19229, 81856, 79270, 5509, 70344, 39424 ], "estimatedBudget" : 3086213.8981674756 }
{ "_id" : ObjectId("5981a80f223e491a58230e5f"), "id" : 1, "name" : "jvbzobhppntd", "managerId" : 18925, "startDate" : "29.04.1999", "finishDate" : "13.10.2008", "projectStatus" : "OPEN", "participants" : [ 46100, 96968, 6676, 56121, 4716, 68901, 43990, 48587, 62547, 30292, 65153, 17551, 27083, 20261, 27097, 50036, 86585, 69890, 18790, 22592, 60774, 93709, 78471, 27157, 4328, 36501, 47296, 16831 ], "estimatedBudget" : 3581496.7068344904 }
{ "_id" : ObjectId("5981a80f223e491a58230e60"), "id" : 4, "name" : "cdspkkqwvwld", "managerId" : 62042, "startDate" : "13.03.1998", "finishDate" : "20.06.2007", "projectStatus" : "OPEN", "participants" : [ 53480, 60897, 23677, 22064, 60807, 66637, 84609, 28378, 87143, 27675, 79283, 94992, 20429, 48769, 91671, 41747, 21651, 91134, 41684, 57228, 51949, 18756, 45679, 87781, 67287, 6902, 27526 ], "estimatedBudget" : 2126283.953787842 }
....
I need to find the busiest employee and list all his projects.
participants array contains employee ids who participate in the project.
I use the following query to find the busiest employee:
db.projects.aggregate(
{
$unwind: '$participants'
},
{
$addFields: {
count: 1
}
},
{
$group: {
_id : '$participants',
participation_count : {
'$sum':'$count'
}
}
},
{
$sort:{participation_count:-1}
},
{
$limit:1
}
)
and this work correctly. But I have no ideas how to list all his projects.
any ideas?
db.projects.aggregate(
[
{
$unwind: '$participants'
},
{
$addFields: {
count: 1
}
},
{
$group: {
_id : '$participants',
participation_count : {'$sum':'$count'},
projectId : {$push: '$id'}
}
},
{
$sort:{participation_count:-1}
},
{
$limit:1
}
],
{
allowDiskUse:true
}
)
Related
Need help to sort these documents:
const docs = Docs.find(
{
'publishedOn.profileId': groupProfile._id,
},
{ sort: { ??? }}
);
I need to find documents which has defined 'publishedOn.profileId' and
sort by 'awards.type' = 'challengeWinner' and by its 'awards.score'
Not all document has awards.type = 'challengeWinner'. I need to
take on the top 'awards.score' = 1, then 2, then 3 and then the rest by 'writtenDate'.
I have no idea how to fix it. Is it possible?
[
{
"_id" : "5FW9EDW8gi3M8R7XK",
"createdAt" : ISODate("2021-06-13T00:11:48.638Z"),
"title" : "My solution",
"writtenDateType" : 4,
"writtenDate" : ISODate("2021-06-13T00:00:00.000Z"),
"userId" : "dC35hwe6XMRhvqWBv",
"publishedOn" : [
{
"profileId" : "36oPw2zxYCpKxfiu2",
"publishedDate" : ISODate("2021-06-13T00:11:48.787Z"),
"userId" : "dC35hwe6XMRhvqWBv"
},
{
"profileId" : "9y2RwJpzzyk29ApiC",
"userId" : "dC35hwe6XMRhvqWBv",
"publishedDate" : ISODate("2021-06-13T00:16:01.529Z")
}
],
"awards" : [
{
"type" : "topPoem",
"score" : 5,
"addedAt" : ISODate("2021-06-24T23:04:10.454Z"),
"updatedAt" : ISODate("2021-06-25T23:30:00.069Z")
},
{
"type" : "challengeWinner",
"score" : 2,
"challengeId" : "9y2RwJpzzyk29ApiC",
"addedAt" : ISODate("2021-06-24T23:04:10.454Z"),
"updatedAt" : ISODate("2021-06-25T23:30:00.069Z")
}
]
},
{
"_id" : "upzvo8BeHyQ9r9Yfv",
"createdAt" : ISODate("2021-06-19T15:35:13.716Z"),
"title" : "Briches",
"writtenDateType" : 2,
"writtenDate" : ISODate("2003-01-01T00:00:00.000Z"),
"userId" : "A32228XMuZqxFe4Kz",
"publishedOn" : [
{
"profileId" : "MLGkCtNyZ64bGKedG",
"publishedDate" : ISODate("2021-06-19T15:35:13.861Z"),
"userId" : "A32228XMuZqxFe4Kz"
},
{
"profileId" : "9y2RwJpzzyk29ApiC",
"userId" : "A32228XMuZqxFe4Kz",
"publishedDate" : ISODate("2021-06-19T15:35:36.280Z")
}
],
"awards" : [
{
"type" : "challengeWinner",
"score" : 1,
"challengeId" : "9y2RwJpzzyk29ApiC",
"addedAt" : ISODate("2021-06-24T22:59:00.948Z"),
"updatedAt" : ISODate("2021-06-25T23:30:00.067Z"),
"claps" : 19,
"clapsUsers" : 4
},
{
"type" : "suggestedHomepage",
"score" : 1,
"addedAt" : ISODate("2021-06-24T22:59:59.981Z"),
"updatedAt" : ISODate("2021-06-24T22:59:59.981Z")
}
]
}
]
I just learned and tried to solve your problem. I used aggregate to do the filter in your data.
First I selected all the items which $match the `publishedOn.profileId".
Then, I $project(ed) the items that are needed. In this case, I took the writtenDate and the matching awards.
In order to choose the needed value from awards, I $filter (ed) the award type.
Last, I did $sort for the award score first and then writtenDate,
db.collection.aggregate([
{
"$match": {
"publishedOn.profileId": "9y2RwJpzzyk29ApiC"
}
},
{
"$project": {
"writtenDate": 1,
"awards": {
"$filter": {
"input": "$awards",
"as": "award",
"cond": {
"$eq": [
"$$award.type",
"challengeWinner"
]
}
}
}
}
},
{
"$sort": {
"awards.score": 1,
"writtenDate": 1,
}
}
])
Working of above query: https://mongoplayground.net/p/MzWQCR2Gshg
Happy Coding !!!
I am having problems aggregating my Product Document in MongoDB.
My Product Document is:
{
"_id" : ObjectId("5d81171c2c69f45ef459e0af"),
"type" : "T-Shirt",
"name" : "Panda",
"description" : "Panda's are cool.",
"image" : ObjectId("5d81171c2c69f45ef459e0ad"),
"created_at" : ISODate("2019-09-17T18:25:48.026+01:00"),
"is_featured" : false,
"sizes" : [
"XS",
"S",
"M",
"L",
"XL"
],
"tags" : [ ],
"pricing" : {
"price" : 26,
"sale_price" : 8
},
"categories" : [
ObjectId("5d81171b2c69f45ef459e086"),
ObjectId("5d81171b2c69f45ef459e087")
],
"sku" : "5d81171c2c69f45ef459e0af"
},
And my Category Document is:
{
"_id" : ObjectId("5d81171b2c69f45ef459e087"),
"name" : "Art",
"description" : "These items are our artsy options.",
"created_at" : ISODate("2019-09-17T18:25:47.196+01:00")
},
My aim is to perform aggregation on the Product Document in order to count the number of items within each Category. So I have the Category "Art", I need to count the products are in the "Art" Category:
My current aggregate:
db.product.aggregate(
{ $unwind : "$categories" },
{
$group : {
"_id" : { "name" : "$name" },
"doc" : { $push : { "category" : "$categories" } },
}
},
{ $unwind : "$doc" },
{
$project : {
"_id" : 0,
"name" : "$name",
"category" : "$doc.category"
}
},
{
$group : {
"_id" : "$category",
"name": { "$first": "$name" },
"items_in_cat" : { $sum : 1 }
}
},
{ "$sort" : { "items_in_cat" : -1 } },
)
Which does actually work but not as I need:
{
"_id" : ObjectId("5d81171b2c69f45ef459e082"),
"name" : null, // Why is the name of the category no here?
"items_in_cat" : 4
},
As we can see the name is null. How can I aggregate the output to be:
{
"_id" : ObjectId("5d81171b2c69f45ef459e082"),
"name" : "Art",
"items_in_cat" : 4
},
We need to use $lookup to fetch the name from Category collection.
The following query can get us the expected output:
db.product.aggregate([
{
$unwind:"$categories"
},
{
$group:{
"_id":"$categories",
"items_in_cat":{
$sum:1
}
}
},
{
$lookup:{
"from":"category",
"let":{
"id":"$_id"
},
"pipeline":[
{
$match:{
$expr:{
$eq:["$_id","$$id"]
}
}
},
{
$project:{
"_id":0,
"name":1
}
}
],
"as":"categoryLookup"
}
},
{
$unwind:{
"path":"$categoryLookup",
"preserveNullAndEmptyArrays":true
}
},
{
$project:{
"_id":1,
"name":{
$ifNull:["$categoryLookup.name","NA"]
},
"items_in_cat":1
}
}
]).pretty()
Data set:
Collection: product
{
"_id" : ObjectId("5d81171c2c69f45ef459e0af"),
"type" : "T-Shirt",
"name" : "Panda",
"description" : "Panda's are cool.",
"image" : ObjectId("5d81171c2c69f45ef459e0ad"),
"created_at" : ISODate("2019-09-17T17:25:48.026Z"),
"is_featured" : false,
"sizes" : [
"XS",
"S",
"M",
"L",
"XL"
],
"tags" : [ ],
"pricing" : {
"price" : 26,
"sale_price" : 8
},
"categories" : [
ObjectId("5d81171b2c69f45ef459e086"),
ObjectId("5d81171b2c69f45ef459e087")
],
"sku" : "5d81171c2c69f45ef459e0af"
}
Collection: category
{
"_id" : ObjectId("5d81171b2c69f45ef459e086"),
"name" : "Art",
"description" : "These items are our artsy options.",
"created_at" : ISODate("2019-09-17T17:25:47.196Z")
}
{
"_id" : ObjectId("5d81171b2c69f45ef459e087"),
"name" : "Craft",
"description" : "These items are our artsy options.",
"created_at" : ISODate("2019-09-17T17:25:47.196Z")
}
Output:
{
"_id" : ObjectId("5d81171b2c69f45ef459e087"),
"items_in_cat" : 1,
"name" : "Craft"
}
{
"_id" : ObjectId("5d81171b2c69f45ef459e086"),
"items_in_cat" : 1,
"name" : "Art"
}
I'm struggling to identified duplicated elements in my MongoDB records, here is my problem :
I have a Mongo collection named "elements".
Example of a record in this collection :
{
"_id" : ObjectId("5d1b2204e851271e80c824b6"),
"name" : "A",
"items" : [
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d7"),
"_id" : ObjectId("5d1b2205e851271e80c82534")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d6"),
"_id" : ObjectId("5d1b2205e851271e80c82533")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d8"),
"_id" : ObjectId("5d1b2205e851271e80c82532")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d5"),
"_id" : ObjectId("5d1b3048e851271e80c826a5")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d5"),
"_id" : ObjectId("5d1b3048e851271e80c826ad")
}
]
}
I would like to identify records where the array "items" contains objects with the same "ref_id".
In my example we can see that the last two objects of the "items" array have the same "ref_id" : ObjectId("5d1b2204e851271e80c823d5").
I tried a bunch of aggregate function but unfortunately couldn't came out with a solution.
The following query can get us the expected output:
db.elements.aggregate([
{
$unwind:"$items"
},
{
$group:{
"_id":"$_id",
"root":{
$first:"$$ROOT"
},
"items":{
$push:"$items"
},
"distinctItems":{
$addToSet: "$items.ref_id"
}
}
},
{
$match:{
$expr:{
$ne:[
{
$size:"$items"
},
{
$size:"$distinctItems"
}
]
}
}
},
{
$addFields:{
"root.items":"$items"
}
},
{
$replaceRoot:{
"newRoot":"$root"
}
}
]).pretty()
Data set:
{
"_id" : ObjectId("5d1b2204e851271e80c824b6"),
"name" : "A",
"items" : [
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d7"),
"_id" : ObjectId("5d1b2205e851271e80c82534")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d6"),
"_id" : ObjectId("5d1b2205e851271e80c82533")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d8"),
"_id" : ObjectId("5d1b2205e851271e80c82532")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d5"),
"_id" : ObjectId("5d1b3048e851271e80c826a5")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d5"),
"_id" : ObjectId("5d1b3048e851271e80c826ad")
}
]
}
{
"_id" : ObjectId("5d654b9d7d0ab652c42315f2"),
"name" : "B",
"items" : [
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d7"),
"_id" : ObjectId("5d1b2205e851271e80c82534")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d6"),
"_id" : ObjectId("5d1b2205e851271e80c82533")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d8"),
"_id" : ObjectId("5d1b2205e851271e80c82532")
}
]
}
Output:
{
"_id" : ObjectId("5d1b2204e851271e80c824b6"),
"name" : "A",
"items" : [
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d7"),
"_id" : ObjectId("5d1b2205e851271e80c82534")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d6"),
"_id" : ObjectId("5d1b2205e851271e80c82533")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d8"),
"_id" : ObjectId("5d1b2205e851271e80c82532")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d5"),
"_id" : ObjectId("5d1b3048e851271e80c826a5")
},
{
"ref_id" : ObjectId("5d1b2204e851271e80c823d5"),
"_id" : ObjectId("5d1b3048e851271e80c826ad")
}
]
}
Explanation: We are populating an array of distinct ref_id from each document and matching if the size of the populated array is equal to the size of actual items array.
I have a issue in MongoDB i'm trying to build a very complex aggregate query, and its work almost as i want it, but i still have trobles, and the problems is i need to move a spefiect field so i can use it later.
My aggregate look like this right now.
db.getCollection('travel_sights').aggregate([{
'$match': {
'preview.photo' : {
'$exists':true
},
'_id': {
'$in' : [ObjectId("5b7af9701fbad410e10f32f7")]
}
}
},{
'$unwind' : '$preview.photo'
}, {
'$lookup':{
'from' : 'media_data',
'localField' : '_id',
'foreignField':'bind',
'as':'media'
}
}])
and it will return data like this.
{
"_id" : ObjectId("5b7af9701fbad410e10f32f7"),
"preview" : {
"photo" : {
"id" : ObjectId("5b7affea1fbad441494a663b"),
"sort" : 0
}
},
"media" : [
{
"_id" : ObjectId("5b7affea1fbad441494a663b")
},
{
"_id" : ObjectId("5b7b002d1fbad441494a663c")
},
{
"_id" : ObjectId("5b7b00351fbad441494a663d")
},
{
"_id" : ObjectId("5b7d9baa1fbad410de638bbb")
},
{
"_id" : ObjectId("5b7d9bae1fbad410e10f32f9")
},
{
"_id" : ObjectId("5b7d9bb11fbad441494a663e")
},
{
"_id" : ObjectId("5b7d9bb41fbad4ff97273402")
},
{
"_id" : ObjectId("5b7d9bb71fbad4ff99527e82")
},
{
"_id" : ObjectId("5b7d9bbb1fbad410de638bbc")
},
{
"_id" : ObjectId("5b7d9bbe1fbad410e10f32fa")
},
{
"_id" : ObjectId("5b7d9bc11fbad441494a663f")
},
{
"_id" : ObjectId("5b7d9bc41fbad4ff97273403")
},
{
"_id" : ObjectId("5b7d9bc71fbad4ff99527e83")
},
{
"_id" : ObjectId("5b7d9bca1fbad410de638bbd")
},
{
"_id" : ObjectId("5b7d9bcd1fbad441494a6640")
},
{
"_id" : ObjectId("5b7d9bd01fbad4ff97273404")
}
]
}
{
"_id" : ObjectId("5b7af9701fbad410e10f32f7"),
"preview" : {
"photo" : {
"id" : ObjectId("5b7b002d1fbad441494a663c"),
"sort" : 0
}
},
"media" : [
{
"_id" : ObjectId("5b7affea1fbad441494a663b")
},
{
"_id" : ObjectId("5b7b002d1fbad441494a663c")
},
{
"_id" : ObjectId("5b7b00351fbad441494a663d")
},
{
"_id" : ObjectId("5b7d9baa1fbad410de638bbb")
},
{
"_id" : ObjectId("5b7d9bae1fbad410e10f32f9")
},
{
"_id" : ObjectId("5b7d9bb11fbad441494a663e")
},
{
"_id" : ObjectId("5b7d9bb41fbad4ff97273402")
},
{
"_id" : ObjectId("5b7d9bb71fbad4ff99527e82")
},
{
"_id" : ObjectId("5b7d9bbb1fbad410de638bbc")
},
{
"_id" : ObjectId("5b7d9bbe1fbad410e10f32fa")
},
{
"_id" : ObjectId("5b7d9bc11fbad441494a663f")
},
{
"_id" : ObjectId("5b7d9bc41fbad4ff97273403")
},
{
"_id" : ObjectId("5b7d9bc71fbad4ff99527e83")
},
{
"_id" : ObjectId("5b7d9bca1fbad410de638bbd")
},
{
"_id" : ObjectId("5b7d9bcd1fbad441494a6640")
},
{
"_id" : ObjectId("5b7d9bd01fbad4ff97273404")
}
]
}
{
"_id" : ObjectId("5b7af9701fbad410e10f32f7"),
"preview" : {
"photo" : {
"id" : ObjectId("5b7b00351fbad441494a663d"),
"sort" : 0,
"primary" : false
}
},
"media" : [
{
"_id" : ObjectId("5b7affea1fbad441494a663b")
},
{
"_id" : ObjectId("5b7b002d1fbad441494a663c")
},
{
"_id" : ObjectId("5b7b00351fbad441494a663d")
},
{
"_id" : ObjectId("5b7d9baa1fbad410de638bbb")
},
{
"_id" : ObjectId("5b7d9bae1fbad410e10f32f9")
},
{
"_id" : ObjectId("5b7d9bb11fbad441494a663e")
},
{
"_id" : ObjectId("5b7d9bb41fbad4ff97273402")
},
{
"_id" : ObjectId("5b7d9bb71fbad4ff99527e82")
},
{
"_id" : ObjectId("5b7d9bbb1fbad410de638bbc")
},
{
"_id" : ObjectId("5b7d9bbe1fbad410e10f32fa")
},
{
"_id" : ObjectId("5b7d9bc11fbad441494a663f")
},
{
"_id" : ObjectId("5b7d9bc41fbad4ff97273403")
},
{
"_id" : ObjectId("5b7d9bc71fbad4ff99527e83")
},
{
"_id" : ObjectId("5b7d9bca1fbad410de638bbd")
},
{
"_id" : ObjectId("5b7d9bcd1fbad441494a6640")
},
{
"_id" : ObjectId("5b7d9bd01fbad4ff97273404")
}
]
}
and what you can se the last data have preview.photo.primary on it, and this field i want to return when i'm done with my aggregate query.
My final query look like this:
db.getCollection('travel_sights').aggregate([{
'$match': {
'preview.photo' : {
'$exists':true
},
'_id': {
'$in' : [ObjectId("5b7af9701fbad410e10f32f7")]
}
}
},{
'$unwind' : '$preview.photo'
}, {
'$lookup':{
'from' : 'media_data',
'localField' : '_id',
'foreignField':'bind',
'as':'media'
}
},{
'$unwind':'$media'
},{
'$project' : {
'preview' : 1,
'media': 1,
}
}, {
'$group': {
'_id':'$media._id',
'primary': {
'$first':'$preview'
}
}
}])
The problem here is when i want $preview return so i can find the primary about it, its allways only return the first where the value not exists, if i use $push the problem is i get every thing.
is there a way so i can pick the right primary value in my return? have trying $addFields to but whitout eny kind of lock.
Travel_sights data:
{
"_id" : ObjectId("5b7af9701fbad410e10f32f7"),
"city_id" : ObjectId("5b6d0cb6222d4c70b803eaeb"),
"activated" : true,
"deleted" : false,
"url" : "url is here",
"name" : "title of it here",
"updated_at" : ISODate("2018-08-22T17:22:27.000Z"),
"content" : "content here",
"preview" : {
"photo" : [
{
"id" : ObjectId("5b7affea1fbad441494a663b"),
"sort" : 0
},
{
"id" : ObjectId("5b7b002d1fbad441494a663c"),
"sort" : 0
},
{
"id" : ObjectId("5b7b00351fbad441494a663d"),
"sort" : 0,
"primary" : true
},
{
"id" : ObjectId("5b7d9baa1fbad410de638bbb"),
"sort" : 0
},
{
"id" : ObjectId("5b7d9bae1fbad410e10f32f9"),
"sort" : 0
},
{
"id" : ObjectId("5b7d9bb11fbad441494a663e"),
"sort" : 0
},
{
"id" : ObjectId("5b7d9bb41fbad4ff97273402"),
"sort" : 0,
"primary" : false
},
{
"id" : ObjectId("5b7d9bb71fbad4ff99527e82"),
"sort" : 0,
"primary" : false
},
{
"id" : ObjectId("5b7d9bbb1fbad410de638bbc"),
"sort" : 0
},
{
"id" : ObjectId("5b7d9bbe1fbad410e10f32fa"),
"sort" : 0
},
{
"id" : ObjectId("5b7d9bc11fbad441494a663f"),
"sort" : 0
},
{
"id" : ObjectId("5b7d9bc41fbad4ff97273403"),
"sort" : 0,
"primary" : false
},
{
"id" : ObjectId("5b7d9bc71fbad4ff99527e83"),
"sort" : 0,
"primary" : false
},
{
"id" : ObjectId("5b7d9bca1fbad410de638bbd"),
"sort" : 0,
"primary" : false
},
{
"id" : ObjectId("5b7d9bcd1fbad441494a6640"),
"sort" : 0,
"primary" : false
},
{
"id" : ObjectId("5b7d9bd01fbad4ff97273404"),
"sort" : 0
}
]
}
}
3 sample foto bind data here:
{
"_id" : ObjectId("5b7affea1fbad441494a663b"),
"file-name" : "55575110311__0F115282-B5A0-4654-AA44-B7DC2C682992.jpeg",
"options" : [
ObjectId("5b6fb855222d4c70b8041093")
],
"type" : "images",
"files" : [
{
"width" : 70,
"height" : 53
},
{
"width" : 400,
"height" : 300
},
{
"width" : 800,
"height" : 600
},
{
"width" : 1600,
"height" : 1200
}
],
"bind" : [
ObjectId("5b7af9701fbad410e10f32f7")
]
}
{
"_id" : ObjectId("5b7b002d1fbad441494a663c"),
"file-name" : "55575110748__E7B07EFD-9F7E-40D6-8B57-38F708E4C0C0.jpeg",
"options" : [
ObjectId("5b6fb855222d4c70b8041093")
],
"type" : "images",
"files" : [
{
"width" : 70,
"height" : 53
},
{
"width" : 400,
"height" : 300
},
{
"width" : 800,
"height" : 600
},
{
"width" : 1600,
"height" : 1200
}
],
"bind" : [
ObjectId("5b7af9701fbad410e10f32f7")
],
"description" : "this is secoudn demo!",
"title" : "demo 3"
}
{
"_id" : ObjectId("5b7b00351fbad441494a663d"),
"file-name" : "paris2.jpg",
"options" : [
ObjectId("5b6fb855222d4c70b8041093")
],
"type" : "images",
"files" : [
{
"width" : 70,
"height" : 53
},
{
"width" : 400,
"height" : 300
},
{
"width" : 800,
"height" : 600
},
{
"width" : 1600,
"height" : 1200
}
],
"bind" : [
ObjectId("5b7af9701fbad410e10f32f7")
],
"description" : "this is a demo1 :)",
"title" : "demo"
}
You can filter out the element from the array where the primary field exists using $filter aggregation and then easily $group with the media._id field and get the $first document value.
Finally your query will be
db.getCollection("travel_sights").aggregate([
{ "$match": {
"preview.photo" : { "$exists":true },
"_id": { "$in" : [ ObjectId("5b7af9701fbad410e10f32f7") ] }
}},
{ "$addFields": {
"preview.photo": {
"$arrayElemAt": [
{ "$filter": {
"input": "$preview.photo",
"as": "photo",
"cond": { "$ne": [ "$$photo.primary", undefined ] }
}}, 0
]
}
}},
{ "$lookup":{
"from" : "media_data",
"localField" : "_id",
"foreignField": "bind",
"as": "media"
}},
{ "$unwind":"$media" },
{ "$project" : { "preview" : 1, "media": 1, }},
{ "$group": {
"_id": "$media._id",
"primary": { "$first": "$preview" }
}}
])
this is my data :
> db.bookmarks.find({"userId" : "56b9b74bf976ab70ff6b9999"}).pretty()
{
"_id" : ObjectId("56c2210fee4a33579f4202dd"),
"userId" : "56b9b74bf976ab70ff6b9999",
"items" : [
{
"itemId" : "28",
"timestamp" : "2016-02-12T18:07:28Z"
},
{
"itemId" : "29",
"timestamp" : "2016-02-12T18:07:29Z"
},
{
"itemId" : "30",
"timestamp" : "2016-02-12T18:07:30Z"
},
{
"itemId" : "31",
"timestamp" : "2016-02-12T18:07:31Z"
},
{
"itemId" : "32",
"timestamp" : "2016-02-12T18:07:32Z"
},
{
"itemId" : "33",
"timestamp" : "2016-02-12T18:07:33Z"
},
{
"itemId" : "34",
"timestamp" : "2016-02-12T18:07:34Z"
}
]
}
I want to have something like (actually i hope the _id can become userId too) :
{
"_id" : "56b9b74bf976ab70ff6b9999",
"items" : [
{ "itemId": "32", "timestamp": "2016-02-12T18:07:32Z" },
{ "itemId": "31", "timestamp": "2016-02-12T18:07:31Z" },
{ "itemId": "30", "timestamp": "2016-02-12T18:07:30Z" }
]
}
What I have now :
> db.bookmarks.aggregate(
... { $match: { "userId" : "56b9b74bf976ab70ff6b9999" } },
... { $unwind: '$items' },
... { $sort: { 'items.timestamp': -1} },
... { $skip: 2 },
... { $limit: 3},
... { $group: { '_id': '$userId' , items: { $push: '$items.itemId' } } }
... ).pretty()
{ "_id" : "56b9b74bf976ab70ff6b9999", "items" : [ "32", "31", "30" ] }
i tried to read the document in mongo and find out i can $push, but somehow i cannot find a way to push such object, which is not defined anywhere in the whole object. I want to have the timestamp also.. but i don't know how should i modified the $group (or others??) to do so. thanks for helping!
This code, which I tested in the MongoDB 3.2.1 shell, should give you the output format that you want:
> db.bookmarks.aggregate(
{ "$match" : { "userId" : "Ursula" } },
{ "$unwind" : "$items" },
{ "$sort" : { "items.timestamp" : -1 } },
{ "$skip" : 2 },
{ "$limit" : 3 },
{ "$group" : { "_id" : "$userId", items: { "$push" : { "myPlace" : "$items.itemId", "myStamp" : "$items.timestamp" } } } } ).pretty()
Running the above will produce this output:
{
"_id" : "Ursula",
"items" : [
{
"myPlace" : "52",
"myStamp" : ISODate("2016-02-13T18:07:32Z")
},
{
"myPlace" : "51",
"myStamp" : ISODate("2016-02-13T18:07:31Z")
},
{
"myPlace" : "50",
"myStamp" : ISODate("2016-02-13T18:07:30Z")
}
]
}
In MongoDB version 3.2.x, you can also use the $out operator in the very last stage of the aggregation pipeline, and have the output of the aggregation query written to a collection. Here is the code I used:
> db.bookmarks.aggregate(
{ "$match" : { "userId" : "Ursula" } },
{ "$unwind" : "$items" },
{ "$sort" : { "items.timestamp" : -1 } },
{ "$skip" : 2 },
{ "$limit" : 3 },
{ "$group" : { "_id" : "$userId", items: { "$push" : { "myPlace" : "$items.itemId", "myStamp" : "$items.timestamp" } } } },
{ "$out" : "ursula" } )
This gives me a collection named "ursula":
> show collections
ursula
and I can query that collection:
> db.ursula.find().pretty()
{
"_id" : "Ursula",
"items" : [
{
"myPlace" : "52",
"myStamp" : ISODate("2016-02-13T18:07:32Z")
},
{
"myPlace" : "51",
"myStamp" : ISODate("2016-02-13T18:07:31Z")
},
{
"myPlace" : "50",
"myStamp" : ISODate("2016-02-13T18:07:30Z")
}
]
}
>
Last of all, this is the input document I used in the aggregation query. You can compare this document to how I coded the aggregation query to see how I built the new items array.
> db.bookmarks.find( { "userId" : "Ursula" } ).pretty()
{
"_id" : ObjectId("56c240ed55f2f6004dc3b25c"),
"userId" : "Ursula",
"items" : [
{
"itemId" : "48",
"timestamp" : ISODate("2016-02-13T18:07:28Z")
},
{
"itemId" : "49",
"timestamp" : ISODate("2016-02-13T18:07:29Z")
},
{
"itemId" : "50",
"timestamp" : ISODate("2016-02-13T18:07:30Z")
},
{
"itemId" : "51",
"timestamp" : ISODate("2016-02-13T18:07:31Z")
},
{
"itemId" : "52",
"timestamp" : ISODate("2016-02-13T18:07:32Z")
},
{
"itemId" : "53",
"timestamp" : ISODate("2016-02-13T18:07:33Z")
},
{
"itemId" : "54",
"timestamp" : ISODate("2016-02-13T18:07:34Z")
}
]
}