Laravel MongoDB - aggregation, ordering query - mongodb

Question

I am wondering how could I achieve a specific result.
Starting of
I am using https://github.com/jenssegers/laravel-mongodb
The code sample below is used to get an array of documents that contains my specific slug in the rewards node. And till that point, everything works as intended.
$array = [
'rewards.slug' => ['$eq' => 'example_slug'],
'expired' => ['$gte' => \Carbon\Carbon::now()->toDateTimeString()]
];
$models = Master::raw(function ($collection) use (&$array) {
return $collection->find(
$array, ["typeMap" => ['root' => 'array', 'document' => 'array']])
->toArray();
});
My example document
{
"_id": {
"$oid": "5be4464eafad20007245543f"
},
"some_int_value": 100,
"some_string_value": "String",
"rewards": [
{
"slug": "example_slug",
"name": "Example slug",
"quantity": 4,
"estimated": {
"value": 18750
}
},
{
"slug": "example_slug",
"name": "Example slug",
"quantity": 1,
"estimated": {
"value": 100
}
},
{
"slug": "other_example",
"name": "Other slug example",
"quantity": 1,
"estimated": {
"value": 100
}
}
],
"expires": "2018-11-08 20:20:45",
}
Desired result
I would like to implement some more complex query, which would do the following.
Retrieve documents that : pseudo select all documents that contain reward "slug": "example_slug", sum the quantity of them, return greater than X quantity documents, order by sum quantity desc
and a very similar one to the above select all documents that contain reward "slug": "example_slug", sum estimated.value, return greater than X estimated.value documents, order by sum of estimated.value desc
If you do need more explanation feel free to ask, I feel like I don't even know where to start with this one.
All help is greatly appreciated

Answer 1

You can use below aggregation in 3.6.
$addFields to create an extra slugcount field to hold the result.
$filter rewards with slug matching example_slug followed by $sum to sum the quantity field.
$match with $gt > X - aggregation expression to filter documents where the sum of all matching quantities is greater than X
$sort slugcount desc and $project with exclusion to remove the slugcount from the final response.
db.colname.aggregate([
{"$addFields":{
"slugcount":
{"$let":{
"vars":{
"mslug":{
"$filter":{
"input":"$rewards",
"cond":{"$eq":["$$this.slug","example_slug"]}
}
}
},
"in":{"$sum":"$$mslug.quantity"}
}}
}},
{"$match":{"slugcount":{"$gt":X}}},
{"$sort":{"slugcount":-1}},
{"$project":{"slugcount":0}}
])
Something like
ModelName::raw(function ($collection) {
return $collection->aggregate([
['$match' => ['expired' => ['$gte' => \Carbon\Carbon::now()->toDateTimeString()]]],
['$addFields' => [
'slugcount'
['$let' => [
'vars' => [
'mslug' => [
'$filter' => [
'input' => '$rewards',
'cond' => ['$eq' => ['$$this.slug','example_slug']]
]
]
],
'in' => ['$sum' => '$$mslug.quantity']
]]
]],
['$match' => ['slugcount'=> ['$gt' => X]]],
['$sort' => ['slugcount' => -1]],
['$project' => ['slugcount' => 0]]]);
});
You can replace quantity with estimated.value for second aggregation.