How to return specific field's value in mongodb

Question

how can I return a specific value for a specific document in MongoDB? For example, I have a schema that looks like:

{
"_id" : "XfCZSje7GjynvMZu7",
"createdAt" : ISODate("2015-03-23T14:52:44.084Z"),
"services" : {
    "password" : {
        "bcrypt" : "$2a$10$tcb01VbDMVhH03mbRdKYL.79FPj/fFMP62BDpcvpoTfF3LPgjHJoq"
    },
    "resume" : {
        "loginTokens" : [ ]
    }
},
"emails" : {
    "address" : "[email protected]",
    "verified" : true
},
"profile" : {
    "companyName" : "comp1",
    "flagged" : true,
    "phoneNum" : "7778883333"
}}

I want to return and store the value for profile.flagged specifically for the document with _id : XfCZSje7GjynvMZu7. So far I have tried:

db.users.find({_id:'myfi3E4YTf9z6tdgS'},{admin:1})

and

db.users.find({_id: 'myfi3E4YTf9z6tdgS'}, {profile:admin});

I want the query to return true or false depending on the assigned value.

Can someone help? Thanks!

Yes, something like that. I want it to return "true" or "false" depending on the value — Trung Tran
– Trung Tran, Commented Mar 25, 2015 at 13:58

JohnnyHK · Accepted Answer · 2015-03-25 14:15:50Z

2

MongoDB queries always return document objects, not single values. So one way to do this is with shell code like:

var flagged =
   db.users.findOne({_id: 'myfi3E4YTf9z6tdgS'}, {'profile.flagged': 1}).profile.flagged;

Note the use of findOne instead of find so that you're working with just a single doc instead of the cursor that you get with find.

edited Mar 25, 2015 at 14:15

answered Mar 25, 2015 at 14:06

JohnnyHK

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Comments

Izzi · Accepted Answer · 2021-01-10 08:46:41Z

1

The correct answer here is the method .distinct() (link here)

Use it like this:

db.users.find({_id:'myfi3E4YTf9z6tdgS'},{admin:1}).distinct('admin')

The result will be: 1 or 0

answered Jan 10, 2021 at 8:46

Izzi

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