For example, I have these documents:
{
"addr": "address1",
"book": "book1"
},
{
"addr": "address2",
"book": "book1"
},
{
"addr": "address1",
"book": "book5"
},
{
"addr": "address3",
"book": "book9"
},
{
"addr": "address2",
"book": "book5"
},
{
"addr": "address2",
"book": "book1"
},
{
"addr": "address1",
"book": "book1"
},
{
"addr": "address15",
"book": "book1"
},
{
"addr": "address9",
"book": "book99"
},
{
"addr": "address90",
"book": "book33"
},
{
"addr": "address4",
"book": "book3"
},
{
"addr": "address5",
"book": "book1"
},
{
"addr": "address77",
"book": "book11"
},
{
"addr": "address1",
"book": "book1"
}
and so on.
How can I make a request, which will describe the top N addresses and the top M books per address?
Example of expected result:
address1 | book_1: 5
| book_2: 10
| book_3: 50
| total: 65
______________________
address2 | book_1: 10
| book_2: 10
|...
| book_M: 10
| total: M*10
...
______________________
addressN | book_1: 20
| book_2: 20
|...
| book_M: 20
| total: M*20
This question is related to
mongodb
aggregation-framework
Using aggregate function like below :
[
{$group: {_id : {book : '$book',address:'$addr'}, total:{$sum :1}}},
{$project : {book : '$_id.book', address : '$_id.address', total : '$total', _id : 0}}
]
it will give you result like following :
{
"total" : 1,
"book" : "book33",
"address" : "address90"
},
{
"total" : 1,
"book" : "book5",
"address" : "address1"
},
{
"total" : 1,
"book" : "book99",
"address" : "address9"
},
{
"total" : 1,
"book" : "book1",
"address" : "address5"
},
{
"total" : 1,
"book" : "book5",
"address" : "address2"
},
{
"total" : 1,
"book" : "book3",
"address" : "address4"
},
{
"total" : 1,
"book" : "book11",
"address" : "address77"
},
{
"total" : 1,
"book" : "book9",
"address" : "address3"
},
{
"total" : 1,
"book" : "book1",
"address" : "address15"
},
{
"total" : 2,
"book" : "book1",
"address" : "address2"
},
{
"total" : 3,
"book" : "book1",
"address" : "address1"
}
I didn't quite get your expected result format, so feel free to modify this to one you need.
Below query will provide exactly the same result as given in the desired response:
db.books.aggregate([
{
$group: {
_id: { addresses: "$addr", books: "$book" },
num: { $sum :1 }
}
},
{
$group: {
_id: "$_id.addresses",
bookCounts: { $push: { bookName: "$_id.books",count: "$num" } }
}
},
{
$project: {
_id: 1,
bookCounts:1,
"totalBookAtAddress": {
"$sum": "$bookCounts.count"
}
}
}
])
The response will be looking like below:
/* 1 */
{
"_id" : "address4",
"bookCounts" : [
{
"bookName" : "book3",
"count" : 1
}
],
"totalBookAtAddress" : 1
},
/* 2 */
{
"_id" : "address90",
"bookCounts" : [
{
"bookName" : "book33",
"count" : 1
}
],
"totalBookAtAddress" : 1
},
/* 3 */
{
"_id" : "address15",
"bookCounts" : [
{
"bookName" : "book1",
"count" : 1
}
],
"totalBookAtAddress" : 1
},
/* 4 */
{
"_id" : "address3",
"bookCounts" : [
{
"bookName" : "book9",
"count" : 1
}
],
"totalBookAtAddress" : 1
},
/* 5 */
{
"_id" : "address5",
"bookCounts" : [
{
"bookName" : "book1",
"count" : 1
}
],
"totalBookAtAddress" : 1
},
/* 6 */
{
"_id" : "address1",
"bookCounts" : [
{
"bookName" : "book1",
"count" : 3
},
{
"bookName" : "book5",
"count" : 1
}
],
"totalBookAtAddress" : 4
},
/* 7 */
{
"_id" : "address2",
"bookCounts" : [
{
"bookName" : "book1",
"count" : 2
},
{
"bookName" : "book5",
"count" : 1
}
],
"totalBookAtAddress" : 3
},
/* 8 */
{
"_id" : "address77",
"bookCounts" : [
{
"bookName" : "book11",
"count" : 1
}
],
"totalBookAtAddress" : 1
},
/* 9 */
{
"_id" : "address9",
"bookCounts" : [
{
"bookName" : "book99",
"count" : 1
}
],
"totalBookAtAddress" : 1
}
Source: Stackoverflow.com