MongoDB select where in array of _id?

Question

is possible in mongo db to select collection\'s documents like in SQL :

SELECT * FROM collection WHERE _id IN (1,2,3,4);

or if i have a

Answer 1

Because mongodb uses bson and for bson is important attribute types. and because _id is ObjectId you must use like this:

db.collection.find( { _id : { $in : [ObjectId('1'),ObjectId('2')] } } );

and in mongodb compass use like this:

{ "_id" : { $in : [ObjectId('1'),ObjectId('2')] } }

Note: objectId in string has 24 length.

Answer 2

In this code list is the array of ids in user collection

var list = ["5883d387971bb840b7399130","5883d389971bb840b7399131","5883d38a971bb840b7399132"]

    .find({ _id: {$in : list}})

Answer 3

if you want to find by user and also by another field like conditionally, you can easily do it like beneath with spread and ternary operator using aggregate and match

 const p_id = patient_id;
    let fetchingReports = await Reports.aggregate([
      ...(p_id
        ? [
            {
              $match: {
                createdBy: mongoose.Types.ObjectId(id),
                patient_id: p_id,
              },
            },
          ]
        : [
            {
              $match: {
                createdBy: mongoose.Types.ObjectId(id),
              },
            },
        

Answer 4

This is not related to mongo query. I was familiar with SQL and used Studio3T IDE to query a mongo database using SQL. If you are one like me, I want to point out that the id value needs to be typecasted. So the query will look like:

SELECT _id from <collectionName>
WHERE _id = ObjectId("5883d387971bb840b7399130");

Answer 5

Easy :)

db.collection.find( { _id : { $in : [1,2,3,4] } } );

taken from: http://www.mongodb.org/display/DOCS/Advanced+Queries#AdvancedQueries-%24in