/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

0 vote230 views1 answer
Vscode tsc.ps1 command not loaded
TypeScript
0 vote255 views1 answer
Use multy line in typescript
TypeScript
0 vote222 views1 answer
Whats updog
TypeScript
1 vote229 views2 answers
Clipping input data to the valid range for imshow with RGB data ([0..1] for floats or [0..255] for integers)
TypeScript
6 votes223 views2 answers
Typescript react onchange event type
TypeScript
6 votes214 views1 answer
Comments pycharm
TypeScript
0 vote218 views1 answer
Replace floats in dataframe
TypeScript
0 vote301 views1 answer
Import lodash issue angular
TypeScript
0 vote210 views1 answer
Deno allow net
TypeScript
0 vote241 views1 answer
Distributed Cron Job
TypeScript