/TypeScript/Mongodb count based on array of ids

Mongodb count based on array of ids

Mongo count elements in array

> db.mycollection.insert({'foo':[1,2,3,4]})
> db.mycollection.insert({'foo':[5,6,7]})

> db.mycollection.aggregate([{$project: { count: { $size:"$foo" }}}])
{ "_id" : ObjectId("5314b5c360477752b449eedf"), "count" : 4 }
{ "_id" : ObjectId("5314b5c860477752b449eee0"), "count" : 3 }

Source: stackoverflow.com

Mongo count elements in array

{ $size: <expression> }

Source: docs.mongodb.com

Mongodb count based on array of ids

db.collection.aggregate([
    { $unwind: "$connects" },

    // count all occurrences
    { "$group": { "_id": {skill: "$skill", parser_id: "$connects.parser_id"}, "count": { "$sum": 1 } }},

    // sum all occurrences and count distinct
    { "$group": { "_id": "$_id.skill", "quantity": { "$sum": 1 } }},

    // (optional) rename the '_id' attribute to 'skill'
    { $project: { 'skill': '$_id', 'quantity': 1, _id: 0 } }
])

Source: stackoverflow.com

Similar codes

8 votes149 views6 answers
Google fonts flutter
TypeScript
1 vote120 views1 answer
Typescript merge union type props
TypeScript
3 votes126 views1 answer
Rospy create package
TypeScript
0 vote135 views2 answers
Window.print div
TypeScript
1 vote132 views1 answer
Vue save page elements to pdf
TypeScript
0 vote128 views1 answer
Interface extending mongoose document object does not contain _doc object typescript
TypeScript
1 vote152 views1 answer
Operator '+' cannot be applied to types 'Number' and 'Number'.
TypeScript
2 votes138 views1 answer
End to end testing vs unit testing
TypeScript
0 vote143 views1 answer
Bootstrap get elements id
TypeScript
0 vote138 views1 answer
Objects all django what is returned
TypeScript