I have highly nested mongodb set of objects, so my collection is:
{
"_id":17846384es,
"company_name":"company1",
"company_location":"city1",
"phone":"xxxxx",
"open_time":"xxx",
"products":[
{
"product_id":"123785",
"product_name":"product1",
"user_votes":[
{
"user_id":1,
"vote":1
},
{
"user_id":2,
"vote":2
}
]
},
{
"product_id":"98765",
"product_name":"product2",
"user_votes":[
{
"user_id":5,
"vote":3
},
{
"user_id":3,
"vote":3
}
]
}
]
}
I used some operation like sort and sum on this sub of documents so i used
db.products.aggregate([
{ $unwind: "$products" },
{ $project: {
company_name: 1,
products: {
product_id: 1,
product_name: 1,
user_votes: 1,
votes: { $sum: "$products.user_votes.vote" }
}
} },
{ $sort: { totalVotes: -1 } },
{
$group: {
_id: "$_id",
company_name: { $first: "$company_name" },
products: { $push: "$products" }
}
}
])
to get this result :
{
"_id":17846384es,
"company_name":"company1",
"products":[
{
"product_id":"98765",
"product_name":"product2",
"user_votes":[
{
"user_id":5,
"vote":3
},
{
"user_id":3,
"vote":3
}
]
"votes":6
},
{
"product_id":"123785",
"product_name":"product1",
"user_votes":[
{
"user_id":1,
"vote":1
},
{
"user_id":2,
"vote":2
}
],
"votes":3
}
]
}
but if product document dosen't exist I have an empty result. I want to get a result with company information even if product document doesn't exist.