How to get a list of nested object only if condition match in mongodb? - mongodb

Question

I am developing application which had company and there are 2 users reviewer & admin inside that company. Now as a super admin I want to display only Reviewer of the all company. with following information
Company Name,
Reviewer Name,
Reviewer Email
My collection is
{
"_id" : ObjectId("58830988b9c5f808fc307ec4"),
"createdat" : ISODate("2017-01-21T07:11:04.218+0000"),
"isActive" : true,
"users" : [
{
"_id" : ObjectId("58830988b9c5f808fc307ec5"),
"createdat" : ISODate("2017-01-21T07:11:04.219+0000"),
"role" : "admin",
"password" : "test",
"email" : "email3#email.com",
"name" : "test"
},
{
"name" : "test",
"email" : "email2#email.com",
"password" : "test",
"role" : "admin",
"createdat" : ISODate("2017-01-21T07:24:42.559+0000"),
"_id" : ObjectId("58830cba24ebfa04f812e544")
},
{
"name" : "test",
"email" : "email1#email.com",
"password" : "test",
"role" : "admin",
"isActive" : true,
"createdat" : ISODate("2017-01-21T07:36:37.337+0000"),
"_id" : ObjectId("58830f85d92f1808e0984306")
},
{
"name" : "reviewName 1",
"email" : "reviewName1#gmail.com",
"password" : "test",
"role" : "reviewer",
"isActive" : true,
"createdat" : ISODate("2017-01-21T07:55:39.727+0000"),
"_id" : ObjectId("588313fba001380a383e077e")
},
{
"name" : "test",
"email" : "test",
"password" : "test",
"role" : "admin",
"isActive" : true,
"createdat" : ISODate("2017-01-21T07:56:52.963+0000"),
"_id" : ObjectId("588314447bbc230c306804c1")
}
],
"companyname" : "Test Company 1",
"__v" : NumberInt(0)
}
{
"_id" : ObjectId("58830988b9c5f808fc307ec4"),
"createdat" : ISODate("2017-01-21T07:11:04.218+0000"),
"isActive" : true,
"users" : [
{
"_id" : ObjectId("58830988b9c5f808fc307ec5"),
"createdat" : ISODate("2017-01-21T07:11:04.219+0000"),
"role" : "admin",
"password" : "test",
"email" : "test4#email.com",
"name" : "test"
},
{
"name" : "test",
"email" : "test3#email.com",
"password" : "test",
"role" : "admin",
"createdat" : ISODate("2017-01-21T07:24:42.559+0000"),
"_id" : ObjectId("58830cba24ebfa04f812e544")
},
{
"name" : "test",
"email" : "test2#email.com",
"password" : "test",
"role" : "admin",
"isActive" : true,
"createdat" : ISODate("2017-01-21T07:36:37.337+0000"),
"_id" : ObjectId("58830f85d92f1808e0984306")
},
{
"name" : "reviewName 2_1",
"email" : "reviewName2_1#gmail.com",
"password" : "test",
"role" : "reviewer",
"isActive" : true,
"createdat" : ISODate("2017-01-21T07:55:39.727+0000"),
"_id" : ObjectId("588313fba001380a383e077e")
},
{
"name" : "reviewName 2_2",
"email" : "reviewName2_2#gmail.com",
"password" : "test",
"role" : "reviewer",
"isActive" : true,
"createdat" : ISODate("2017-01-21T07:56:52.963+0000"),
"_id" : ObjectId("588314447bbc230c306804c1")
}
],
"companyname" : "Test Company 2",
"__v" : NumberInt(0)
}
So I would Like to get Following Data
Company Name : Test Company 1,
Reviewer Name : reviewName 1,
Reviewr Email : reviewName1#gmail.com
Company Name : Test Company 2,
Reviewer Name : reviewName 2_1,
Reviewer Email : reviewName2_1#gmail.com
Company Name : Test Company 2,
Reviewer Name : reviewName 2_2,
Reviewer Email : reviewName2_2#gmail.com
There will be lot's of companies, so I don't want to go through with loop and use require information in array. because there will be thousands of company and each company have hundreds of reviewer and admin. So If we go through loop then it will be time consuming. I want to get this data only from collection. So I am looking for the query or condition which gives me only require information.
Can someone help me to get these data-only.

Answer 1

You need to use MongoDB aggregation framework for getting the data according to your requirement.
This query will return data in the desired form.
db.collection.aggregate([
{
"$unwind": "$users"
},
{
"$match": {
"users.role":"reviewer"
}
},
{
"$project": {
"_id":0,
"Company Name" : "$companyname",
"Reviewer Name" : "$users.name",
"Reviewer Email" : "$users.email"
}
}
])