The data I have is:
[
{ type: 'software' },
{ type: 'hardware' },
{ type: 'software' },
{ type: 'network' },
{ type: 'test' },
...
]
I want to create a MongoDB group by aggregation pipeline to return the data like this: I only want 3 objects in result the third object in result {_id: 'other', count: 2}, This should be the sum of counts of type other that software and hardware
[
{_id: 'software', count: 2},
{_id: 'hardware', count: 1},
{_id: 'other', count: 2},
]
This is the exact query (MongoPlayground) that you need if those data are separate documents. Just add $project stage before group and then $switch operator. (If those field data are number, you might wanna check $bucket
db.collection.aggregate([
{
"$project": {
type: {
"$switch": {
"branches": [
{
"case": {
"$eq": [
"$type",
"software"
]
},
"then": "software"
},
{
"case": {
"$eq": [
"$type",
"hardware"
]
},
"then": "hardware"
}
],
default: "other"
}
}
}
},
{
"$group": {
"_id": "$type",
"count": {
"$sum": 1
}
}
}
])
Also, I'd like to recommend avoiding field name
type. Actually it doesn't reserve in MongoDB, but however it could bring conflicts with some drivers since, in schema/model files, type fields are referred to the exact BSON type of the field.