Reputation: 59
How I can get the total number of seats available for a particular movie (seats present in all the theatres for that movie) from the mongodb schema below.
I need to write a mongo query to get the results
{
"_id" : ObjectId("5d637b5ce27c7d60e5c42ae7"),
"name" : "Bangalore",
"movies" : [
{
"name" : "KGF",
"theatres" : [
{
"name" : "PVR",
"seats" : 45
},
{
"name" : "IMAX",
"seats" : 46
}
]
},
{
"name" : "Avengers",
"theatres" : [
{
"name" : "IMAX",
"seats" : 50
}
]
}
],
"_class" : "com.BMS_mongo.ZZ_BMS_mongo_demo.Entity.CityInfo"
}
I have written this code :
db.cities.aggregate( [
{ "$unwind" : "$movies" }, { "$unwind" : "$theatres" } ,
{ "$group" : { _id : "$movies.theatre`enter code here`s.seats" ,
total : { "$sum" : "$seats" } }
}
] )
My schema:
Upvotes: 1
Views: 111
Reputation: 59
I got the answer using this query ...
db.cities.aggregate( [
{ "$match" : { "name" : "Bangalore" } },
{ "$unwind" : "$movies" } ,
{ "$match" : {"movies.name" : "KGF"} },
{ "$unwind" : "$theatres" },
{ "$group" : { _id : "$movies.name", total : { "$sum" : "$movies.theatres.seats"
} } }
] )
Upvotes: 0
Reputation: 982
Query:
db.movie.aggregate([{ $unwind: { path: "$movies",} },
{ $unwind: { path: "$movies.theatres",} },
{ $group: { _id: "$movies.name", "moviename": { $first: "$movies.name" },
"totalSeats": { $sum: "$movies.theatres.seats" }} }])
Upvotes: 0
Reputation: 3010
The following query can get us the expected output:
db.collection.aggregate([
{
$unwind:"$movies"
},
{
$unwind:"$movies.theatres"
},
{
$group:{
"_id":"$movies.name",
"movie":{
$first:"$movies.name"
},
"totalSeats":{
$sum:"$movies.theatres.seats"
}
}
},
{
$project:{
"_id":0
}
}
]).pretty()
Data set:
{
"_id" : ObjectId("5d637b5ce27c7d60e5c42ae7"),
"name" : "Bangalore",
"movies" : [
{
"name" : "KGF",
"theatres" : [
{
"name" : "PVR",
"seats" : 45
},
{
"name" : "IMAX",
"seats" : 46
}
]
},
{
"name" : "Avengers",
"theatres" : [
{
"name" : "IMAX",
"seats" : 50
}
]
}
],
"_class" : "com.BMS_mongo.ZZ_BMS_mongo_demo.Entity.CityInfo"
}
Output:
{ "movie" : "Avengers", "totalSeats" : 50 }
{ "movie" : "KGF", "totalSeats" : 91 }
Upvotes: 3