How to pull array from array in Mongo DB

Question

I have a nested array structured like this

 {
 "_id": "5dff75968102f11e20ae888e",
 "docID": "Employees",
 "data": [
     [
     "234768237",
     "Value1",
     ],
     [
     "234768238",
     "Value2"
     ],
     [
     "234768239",
     "Value3"
     ]
 ]
 }

Inside the nested data array, first element is employee ID, Ex: 234768237. I would want to pass an array of employee ID's and delete the matching ones, for ex : [234768237, 234768238]

What i have tried so far

    let employeeIDArray =  [234768237, 234768238];
    collection.updateOne(
        { docID: "Employees" },
        {
            $pull: {
                "data.$[]": { "0": { $each: employeeIDArray } }
            }
        }
    );

Tom Slabbaert · Accepted Answer · 2019-12-25 16:13:42Z

2

You're close, try:

let employeeIDArray =  [234768237, 234768238];
collection.updateOne(
    { docID: "Employees" },
    {
        $pull: {
            "data": { $in: employeeIDArray } 
        }
    }
);

The $each modifier is only available for $push and $addToSet actions, read more about it here.

EDIT:

For Nested Array use $pullAll instead of $pull like so:

collection.updateOne(
    { docID: "Employees" },
    {
      $pullAll: {
         "data.$[]":  employeeIDArray
    }
});

edited Dec 25, 2019 at 16:13

answered Dec 25, 2019 at 15:47

Tom Slabbaert

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6 Comments

Ram Kumar Over a year ago

Thanks for you suggestion, but it doesn't remove the elements. Please note that data[] contains arrays in the question. I'm trying to delete the element from the nested array.

Tom Slabbaert Over a year ago

oops mb, what mongo version are you on?

Ram Kumar Over a year ago

I'm using the mongo db atlas.

Tom Slabbaert Over a year ago

mb its just what i was testing on, changed to data.

Ram Kumar Over a year ago

It still doesn't work, note that employeeIDArray array contains only 0th element, i guess your solution is still not matching based on the 0th element inside the array.

|

Abhinandan Kothari · Accepted Answer · 2019-12-26 10:04:58Z

0

If you are using MongoDB's latest version then you can use below query to update using aggregation pipeline:

collection.updateOne(
    { docId: "Employees" }, 
    [ { 
        $set: { 
            data: { 
                $filter: { 
                    input: "$data", 
                    cond: { $in: [ { $arrayElemAt: [ "$$this", 0 ] }, [ "234768237", "234768238" ] ] } }
                }
            } 
    } ], 
    { upsert: true }
)

answered Dec 26, 2019 at 10:04

Abhinandan Kothari

3033 silver badges15 bronze badges

4 Comments

Ram Kumar Over a year ago

Hi, i'm getting error 'BSON field \'update.updates.u\' is the wrong type \'array\', expected type \'object\'', with your sugggestion.

Abhinandan Kothari Over a year ago

I think it is a MongoDB version related problem that you are facing. In the latest 4.2 version, you can update the document using the aggregation pipeline as given above. What version of MongoDB are you using?

Ram Kumar Over a year ago

I'm using MongoDB atlas

Abhinandan Kothari Over a year ago

You can upgrade the version of MongoDB in Atlas if you are using the cluster of Tier 10 or higher. -- docs.atlas.mongodb.com/scale-cluster/#scale-cluster-version

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