Get last and minimal values from grouped documents - mongodb

Question

My document model looks like:
{
"model": "ABC123",
"date": "2018-12-24T23:00:00.000+0000",
"price": "2000" ,
}
I would like to retrive collection to get array of documents:
[
{ "_id" : "ABC123", "newestDate" : ISODate("2018-12-26T23:00:00Z"), "newestPrice" : 2801.33, "lowestPriceAtAll": 1300 },
{ "_id" : "ABC124", "newestDate" : ISODate("2018-12-26T23:00:00Z"), "newestPrice" : 2801.33, "lowestPriceAtAll": 990}
]
where _id is model field, newestPrice is price of newest document (grouped by model) and lowestPriceAtAll is lowest price in all documents with the same model.
I grilled two queries.
First is to find lowest price documents:
offers.aggregate([
{ $sort: { "model": 1, "price": 1 }},
{
$group: {
_id: "$model",
lowestPrice: { "$first": "$price" },
lowestPriceDate: { "$first": "$date"},
}
}
])
the second is to find newest documents:
offers.aggregate([
{ $sort: { "model": 1, "date": -1 }},
{
$group: {
_id: "$model",
newestDate: { "$first": "$date" },
newestPrice: { "$first": "$price"},
}
}
])
Is it possible to merge these two queries into one? (the most important thing is that documents have to be grouped by model field).

Answer 1

you can use $facet
db.offers.aggregate([
{$facet :{
lowest: [
{ $sort: { "model": 1, "price": 1 }},
{
$group: {
_id: "$model",
lowestPrice: { "$first": "$price" },
lowestPriceDate: { "$first": "$date"},
}
}
],
newest: [
{ $sort: { "model": 1, "date": -1 }},
{
$group: {
_id: "$model",
newestDate: { "$first": "$date" },
newestPrice: { "$first": "$price"},
}
}
]
}}
])