MongoDB and Aggregation Framework - mongodb

I have the following collection in mongodb.
{ "_id" : ObjectId("519a35ee8f2ceda43f42add5"), "articulo" : "Sobre mongodb", "autor" : "xxxx1", "calificacion" : 3 }
{ "_id" : ObjectId("519a360b8f2ceda43f42add6"), "articulo" : "Aggregation framework", "autor" : "xxxx1", "calificacion" : 5 }
{ "_id" : ObjectId("519a361b8f2ceda43f42add7"), "articulo" : "Sobre journal", "autor" : "xxxx2", "calificacion" : 4 }
{ "_id" : ObjectId("519a362e8f2ceda43f42add8"), "articulo" : "Manipulando datos", "autor" : "xxxx1", "calificacion" : 2 }
{ "_id" : ObjectId("519a36418f2ceda43f42add9"), "articulo" : "MongoDB for dba", "autor" : "xxxx2", "calificacion" : 5 }
{ "_id" : ObjectId("519a4aa18f2ceda43f42adda"), "articulo" : "ejemplo2", "autor" : "xxxx1", "calificacion" : 5 }
I want to count the number of the articles (articulos) with max grade (calificacion) by author(autor).
xxxx1 has 2 articles with grade of 5
xxxx2 has 1 articles with grade of 5
(I don't know what's the max grade)
I've tried this:
db.ejemplo.aggregate([
{$group:{_id: "$autor" , calificacion:{$max:"$calificacion" }}}
])
but I only get the authors with max grade. Could I do it with Aggregation Framework?

You can try the aggregation operation like this:
db.ejemplo.aggregate([
{ $group : { _id : { autor : "$autor",
calificacion : "$calificacion" },
articulos : { $sum : 1 },
}},
{ $sort : { "_id.calificacion" : -1 }},
{ $group : { _id : "$_id.autor",
calificacion : { $first : "$_id.calificacion" },
articulos : { $first : "$articulos" },
}}
])
And the result is like this:
{
"result" : [
{
"_id" : "xxxx1",
"calificacion" : 5,
"articulos" : 2
},
{
"_id" : "xxxx2",
"calificacion" : 5,
"articulos" : 1
}
],
"ok" : 1
}
Thanks,
Linda

Related

mongodb $unwind empty array

With this data:
{
"_id" : ObjectId("576948b4999274493425c08a"),
"virustotal" : {
"scan_id" : "4a6c3dfc6677a87aee84f4b629303c40bb9e1dda283a67236e49979f96864078-1465973544",
"sha1" : "fd177b8c50b457dbec7cba56aeb10e9e38ebf72f",
"resource" : "4a6c3dfc6677a87aee84f4b629303c40bb9e1dda283a67236e49979f96864078",
"response_code" : 1,
"scan_date" : "2016-06-15 06:52:24",
"results" : [
{
"sig" : "Gen:Variant.Mikey.29601",
"vendor" : "MicroWorld-eScan"
},
{
"sig" : null,
"vendor" : "nProtect"
},
{
"sig" : null,
"vendor" : "CAT-QuickHeal"
},
{
"sig" : "HEUR/QVM07.1.0000.Malware.Gen",
"vendor" : "Qihoo-360"
}
]
}
},
{
"_id" : ObjectId("5768f214999274362f714e8b"),
"virustotal" : {
"scan_id" : "3d283314da4f99f1a0b59af7dc1024df42c3139fd6d4d4fb4015524002b38391-1466529838",
"sha1" : "fb865b8f0227e9097321182324c959106fcd8c27",
"resource" : "3d283314da4f99f1a0b59af7dc1024df42c3139fd6d4d4fb4015524002b38391",
"response_code" : 1,
"scan_date" : "2016-06-21 17:23:58",
"results" : [
{
"sig" : null,
"vendor" : "Bkav"
},
{
"sig" : null,
"vendor" : "ahnlab"
},
{
"sig" : null,
"vendor" : "MicroWorld-eScan"
},
{
"sig" : "Mal/DrodZp-A",
"vendor" : "Qihoo-360"
}
]
}
}
I'm trying to group by and count the vendor when sig is not null in order to obtain something like:
{
"_id" : "Qihoo-360",
"count" : 2
},
{
"_id" : "MicroWorld-eScan",
"count" : 1
},
{
"_id" : "Bkav",
"count" : 0
},
{
"_id" : "CAT-QuickHeal",
"count" : 0
}
At the moment with this code:
db.analysis.aggregate([
{ $unwind: "$virustotal.results" },
{
$group : {
_id : "$virustotal.results.vendor",
count : { $sum : 1 }
}
},
{ $sort : { count : -1 } }
])
I'm getting everything:
{
"_id" : "Qihoo-360",
"count" : 2
},
{
"_id" : "MicroWorld-eScan",
"count" : 2
},
{
"_id" : "Bkav",
"count" : 1
},
{
"_id" : "CAT-QuickHeal",
"count" : 1
}
How can I count 0 if the sig is null?
You need a conditional expression in your $sum operator that will check if the "$virustotal.results.sig" key is null by using the comparison operator $gt (as specified in the documentation's BSON comparsion order)
You can restructure your pipeline by adding this expression as follows:
db.analysis.aggregate([
{ "$unwind": "$virustotal.results" },
{
"$group" : {
"_id": "$virustotal.results.vendor",
"count" : {
"$sum": {
"$cond": [
{ "$gt": [ "$virustotal.results.sig", null ] },
1, 0
]
}
}
}
},
{ "$sort" : { "count" : -1 } }
])
Sample Output
/* 1 */
{
"_id" : "Qihoo-360",
"count" : 2
}
/* 2 */
{
"_id" : "MicroWorld-eScan",
"count" : 1
}
/* 3 */
{
"_id" : "Bkav",
"count" : 0
}
/* 4 */
{
"_id" : "CAT-QuickHeal",
"count" : 0
}
/* 5 */
{
"_id" : "nProtect",
"count" : 0
}
/* 6 */
{
"_id" : "ahnlab",
"count" : 0
}
I changed the null with None and the numbers increased but seems not correct yet.
Basically doing the query in mongoshell I get like
{
"_id" : "Kaspersky",
"count" : 176.0
}
from python:
Kaspersky 64
one of these 2 is wrong :)
So I'm trying to investigate what part of the query in python is not correctly written compared to the mongo shell one.
I did a simple query:
In mongoshell:
rtmp = results_db.analysis.count( { "virustotal.results" : { "$elemMatch" : { "vendor": "Kaspersky", "sig": {"$ne": "null"} } }})
results: 176
db.analysis.count( { "virustotal.results" : { $elemMatch : { "vendor": "Kaspersky", "sig": {$gt: null} } }})
results: 0
Then I tried in python:
rtmp = results_db.analysis.count( { "virustotal.results" : { "$elemMatch" : { "vendor": "Kaspersky", "sig": {"$ne": "null"} } }})
results: 568
rtmp = results_db.analysis.count( { "virustotal.results" : { "$elemMatch" : { "vendor": "Kaspersky", "sig": {"$ne": "None"} } }})
results: 568
rtmp = results_db.analysis.count( { "virustotal.results" : { "$elemMatch" : { "vendor": "Kaspersky", "sig": {"$gt": "None"} } }})
results: 64
rtmp = results_db.analysis.count( { "virustotal.results" : { "$elemMatch" : { "vendor": "Kaspersky", "sig": {"$gt": "null"} } }})
results: 6
hard to says what is the correct value! I suppose 176 but not able to reproduce in python...

Mongodb sort by sum of keys

I have a json document
{
{
"_id" : ObjectId("5715c4bbac530eb3018b456a"),
"content_id" : "5715c4bbac530eb3018b4569",
"views" : NumberLong(200),
"likes" : NumberLong(100),
"comments" : NumberLong(0)
},
{
"_id" : ObjectId("5715c4bbac530eb3018b4568"),
"content_id" : "5715c4bbac530eb3018b4567",
"views" : NumberLong(300),
"likes" : NumberLong(200),
"comments" : NumberLong(0)
},
{
"_id" : ObjectId("5715c502ac530ee5018b4956"),
"content_id" : "5715c502ac530ee5018b4955",
"views" : NumberLong(500),
"likes" : NumberLong(0),
"comments" : NumberLong(200)
}
}
How can we sort the document order by SUM("views", "likes", "comments")
something like in mysql
SELECT SUM(key1, key2, key3) AS key
FROM document
ORDER BY key
Thanks in advance.
First do a projection to obtain the sum of all the likes, views and comments, then sort based on that sum. I am considering group by content_id if is needed in the second snippet
db.test.aggregate([
{ $project : { "_id" : "$content_id", "total" : { $add : [ "$likes", "$views", "$comments"]}}},
{ $sort : { "total" : 1 }}
])
If you need a group operation if content_id can be duplicated
db.test.aggregate([
{ $project : { "_id" : "$content_id", "total" : { $add : [ "$likes", "$views", "$comments"]}}},
{ $group : { "_id" : "$_id" , totalPerId : { $sum : "$total" }}},
{ $sort : { "total" : 1 }}
])
Based on your test data, you will get:
{ "_id" : "5715c502ac530ee5018b4955", "totalPerId" : NumberLong(700) }
{ "_id" : "5715c4bbac530eb3018b4567", "totalPerId" : NumberLong(500) }
{ "_id" : "5715c4bbac530eb3018b4569", "totalPerId" : NumberLong(300) }

MongoDB Aggregation - return default value for documents that don't match query

I'm having trouble figuring out the right aggregation pipe operations to return the results I need.
I have a collection similar to the following :-
{
"_id" : "writer1",
"Name" : "writer1",
"Website" : "website1",
"Reviews" : [
{
"Film" : {
"Name" : "Jurassic Park",
"Genre" : "Action"
},
"Score" : 4
},
{
"Technology" : {
"Name" : "Mad Max",
"Genre" : "Action"
},
"Score" : 5
}
]
}
{
"_id" : "writer2",
"Name" : "writer2",
"Website" : "website1",
"Reviews" : [
{
"Technology" : {
"Name" : "Mad Max",
"Genre" : "Action"
},
"Score" : 5
}
]
}
And this is my aggregation so far : -
db.writers.aggregate([
{ "$unwind" : "$Reviews" },
{ "$match" : { "Reviews.Film.Name" : "Jurassic Park" } },
{ "$group" : { "_id" : "$Website" , "score" : { "$avg" : "$Reviews.Score" },
writers :{ $push: { name:"$Name", score:"$Reviews.Score" } }
}}
])
This returns only writers who have a review of the matching film and also only websites that have at least 1 writer who has reviewed the film,
however, I need to return all websites containing a list of their all writers, with a score of 0 if they haven't written a review for the specified film.
so, I am currently getting : -
{ "_id" : "website1", "score" : 4, "writers" : [ { "name" : "writer1", "score" : 4 } ] }
When I actually need : -
{ "_id" : "website1", "score" : 2, "writers" : [ { "name" : "writer1", "score" : 4 },{ "name" :"writer2", "score" : 0 } ] }
Can anyone point me in the right direction?
Cheers

$avg in mongodb aggregation

Document looks like this:
{
"_id" : ObjectId("361de42f1938e89b179dda42"),
"user_id" : "u1",
"evaluator_id" : "e1",
"candidate_id" : ObjectId("54f65356294160421ead3ca1"),
"OVERALL_SCORE" : 150,
"SCORES" : [
{ "NAME" : "asd", "OBTAINED_SCORE" : 30}, { "NAME" : "acd", "OBTAINED_SCORE" : 36}
]
}
Aggregation function:
db.coll.aggregate([ {$unwind:"$SCORES"}, {$group : { _id : { user_id : "$user_id", evaluator_id : "$evaluator_id"}, AVG_SCORE : { $avg : "$SCORES.OBTAINED_SCORE" }}} ])
Suppose if there are two documents with same "user_id" (say u1) and different "evaluator_id" (say e1 and e2).
For example:
1) Average will work like this ((30 + 20) / 2 = 25). This is working for me.
2) But for { evaluator_id : "e1" } document, score is 30 for { "NAME" : "asd" } and { evaluator_id : "e2" } document, score is 0 for { "NAME" : "asd" }. In this case, I want the AVG_SCORE to be 30 only (not (30 + 0) / 2 = 15).
Is it possible through aggregation??
Could any one help me out.
It's possible by placing a $match between the $unwind and $group aggregation pipelines to first filter the arrays which match the specified condition to include in the average computation and that is, score array where the obtained score is not equal to 0 "SCORES.OBTAINED_SCORE" : { $ne : 0 }
db.coll.aggregate([
{
$unwind: "$SCORES"
},
{
$match : {
"SCORES.OBTAINED_SCORE" : { $ne : 0 }
}
},
{
$group : {
_id : {
user_id : "$user_id",
evaluator_id : "$evaluator_id"
},
AVG_SCORE : {
$avg : "$SCORES.OBTAINED_SCORE"
}
}
}
])
For example, the aggregation result for this document:
{
"_id" : ObjectId("5500aaeaa7ef65c7460fa3d9"),
"user_id" : "u1",
"evaluator_id" : "e1",
"candidate_id" : ObjectId("54f65356294160421ead3ca1"),
"OVERALL_SCORE" : 150,
"SCORES" : [
{
"NAME" : "asd",
"OBTAINED_SCORE" : 0
},
{
"NAME" : "acd",
"OBTAINED_SCORE" : 36
}
]
}
will yield:
{
"result" : [
{
"_id" : {
"user_id" : "u1",
"evaluator_id" : "e1"
},
"AVG_SCORE" : 36
}
],
"ok" : 1
}

Do $sort works for sub array document

I have a collection which has a field of array kind. I want to sort on the basis of a field of sub-array but Mongo is not sorting the data.
My collection is:
{
"_id" : ObjectId("51f1fcc08188d3117c6da351"),
"cust_id" : "abc123",
"ord_date" : ISODate("2012-10-03T18:30:00Z"),
"status" : "A",
"price" : 25,
"items" : [{
"sku" : "ggg",
"qty" : 7,
"price" : 2.5
}, {
"sku" : "ppp",
"qty" : 5,
"price" : 2.5
}]
}
My Query is:
db.orders.aggregate([
{ "$unwind" : "$items"} ,
{ "$match" : { }} ,
{ "$group" : { "items" : { "$addToSet" : { "sku" : "$items.sku"}} , "_id" : { }}} ,
{ "$sort" : { "items.sku" : 1}} ,
{ "$project" : { "_id" : 0 , "items" : 1}}
])
Result is:
"result" : [
{
"items" : [
{
"sku" : "ppp"
},
{
"sku" : "ggg"
}
]
}
],
"ok" : 1
}
Whereas "sku":"ggg" should come first when it is ascending.
You weant to do the sort BEFORE you regroup:
db.orders.aggregate([
{ "$unwind" : "$items"} ,
{ "$sort" : { "items.sku" : 1}},
{ "$match" : { }} ,
{ "$group" : { "items" : { "$push" : { "sku" : "$items.sku"}} , "_id" : null}} ,
{ "$project" : { "_id" : 0 , "items" : 1}}
])