Mongo db query for finding object type

Question

I've 1000's of users and user data looks like the below. Some users have the devices as [{some data}] (array), some users have devices as {some data} , and some users have devices as empty [] .

I need mongodb query to find the userslist with devices {some data} . Here is the sample of my users data.

 { "_id" : ObjectId("56fe07bab95708fa18d45ac4"), "username" : "abcd", "devices" : [] }, { "_id" : ObjectId("56fe07bab95708fa18d45df7"), "username" : "efgh", "devices" : [ { "_id" : ObjectId("5827804ef659a60400e12fcb"), "devicetype" : "web" } ], }, { "_id" : ObjectId("56fe07bab95708fa18d45ae8"), "username" : "efgh", "devices" : { "_id" : ObjectId("5951ea8b47abe300046ea26e"), "devicetype" : "web" } }, { "_id" : ObjectId("56fe07bab95708fa18d45b5b"), "username" : "ijkl", "devices" : [ { "_id" : ObjectId("59bd2317eeff3200049a2ba6"), "devicetype" : "ios" "devicetoken" : "1abffaa4419d498b48d0bf982" } ], }, { "_id" : ObjectId("56fe07bab95708fa18d46102"), "username" : "efgh", "devices" : { "_id" : ObjectId("58c433da28841d00040d3cdb"), "devicetype" : "web" } }, { "_id" : ObjectId("56fe07bab95708fa18d46177"), "username" : "efgh", "devices" : { "_id" : ObjectId("59d073d96974d20004a4bb9f"), "devicetype" : "web" } }, { "_id" : ObjectId("56fe07bab95708fa18d456c9"), "username" : "ijkl", "devices" : [ { "_id" : ObjectId("59b93dd2e6673c00044cca49"), "devicetype" : "ios" "devicetoken" : "1abffaa4419d498b48d0bf982" } ], }, { "_id" : ObjectId("56fe07bab95708fa18d456f4"), "username" : "abcd", "devices" : [] }

Answer 1

You can use $type operator like this

db.collection.find( { "devices" : { $type : "object" } } );

or

db.collection.find({ "devices": { $not: { $type: "array" } }})

Answer 2

Update :

Try one of below query as per your requirement (remove empty objects or keep only empty objects):

db.device.find( {$and:[ {devices:{ $type : "object" }},{devices:{$not: { $type: "array" }}}], devices:{$ne:{}}} );

db.device.find( {$and:[ {devices:{ $type : "object" }},{devices:{$not: { $type: "array" }}}], devices:{$eq:{}}} );

Check this screenshot:

Moreover, please note that you have duplicate keys ( _id ) in your data set which means those data sets are not inserted into your DB. So query will obviously won't give proper results.

Edit :

OP removed duplicate keys from data set.

Answer 3

You can use $type operator.

Find more detail on this link https://docs.mongodb.com/manual/reference/operator/query/type/