/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 vote197 views1 answer
Open dialog
TypeScript
5 votes161 views3 answers
Typescript convert date to string format dd/mm/yyyy
TypeScript
1 vote171 views1 answer
Mat input datetime-local now
TypeScript
0 vote146 views1 answer
Online ts compiler
TypeScript
0 vote142 views1 answer
Unable to determine application id: com.android.tools.idea.run.ApkProvisionException: No outputs for the main artifact of variant: debug
TypeScript
0 vote175 views1 answer
Mat-autocomplete options dropdown does not stick when scrolling
TypeScript
0 vote198 views1 answer
How to print certain elements of an array
TypeScript
0 vote170 views1 answer
Vercel react redirects to index html
TypeScript
0 vote163 views2 answers
Giving arguments to main function in c
TypeScript
2 votes172 views1 answer
Add elements to middle of array using splice
TypeScript