Group and slice array
@Aggregation(pipeline = {
"{ $match: {'category':{$regex : ?0, $options: 'i'}}}",
"{ $group: { _id: {category:'$category'}, data: { $push: '$$ROOT' } } }",
"{ $project: { _id: 0, category:'$_id.category', videos:{ $slice:['$data',?1,?2]} }"
})
Use MongoPlayground to learn and tune queries
https://mongoplayground.net/p/lhl5nqbRHta
Some examples:
1. Select max N of a group: (https://mongoplayground.net/p/h79lRA01Jop)
db.collection.aggregate([
{
"$match": {}
},
{
"$group": {
"_id": {
"name": "$name"
},
"data": {
"$push": "$$ROOT"
}
}
},
{
"$project": {
"_id": 0,
"name": "$_id.name",
"videos": {
"$slice": [
"$data",
2
]
}
}
}
])
