How to retrieve the all documents of an array except one document which contains field of a particular value in MongoDB?

Question

db.sample.find():
 {_id:1, locations: [{vname: "edd", distr: "prakasam"}, {vname: "vij", distr: "krishna"}, {vname: "kakani", distr: "guntur"}]};

I want to find the locations other than vname: "vij"

My result could be

{_id: 1, locations: [{vname: "edd", distr: "prakasam"}, {vname: "kakani", distr: "guntur"}]};

I tried with the following queries but couldn't helped me out.

db.sample.find({'locations.$.vname': {$ne: 'vij'}})

It is returning entire document but I need to exclude this document.

Any Help is appreciable.

score 2 · Accepted Answer · answered Jan 31 '17 at 20:12

2

Use $redact. $$PRUNE when locations array matches vname as vij

db.sample.aggregate({
    $redact: {
        $cond: [{
                $eq: ["$vname", "vij"]
            },
            "$$PRUNE",
            "$$DESCEND"
        ]
    }
});

answered Jan 31 '17 at 20:12

s7vr

73,656
11
106
127

Nice! I didn't know about "$redact" – Tarush Arora Jan 31 '17 at 20:16
http://stackoverflow.com/a/24032549/122005 – chridam Jan 31 '17 at 20:17
Awesome, it's really helped me alot. Thank you. – Sandeep sandy Jan 31 '17 at 20:23

score 0 · Answer 2 · answered Jan 31 '17 at 19:43

0

Try this:

> db.sample.find({"locations.vname": {$ne: "vij"}})

answered Jan 31 '17 at 19:43

Natalja Olefire

442
5
9

Not working, I tried. – Sandeep sandy Jan 31 '17 at 19:49
Just from my mongo shell - works. What is your MongoDB version? Are you using a shell? – Natalja Olefire Jan 31 '17 at 19:59
Version 3.2.6 , I'm using cmd prompt in windows. – Sandeep sandy Jan 31 '17 at 20:06
Try to start Mongo Shell and do the same inside shell. Just type mongo in cmd – Natalja Olefire Jan 31 '17 at 20:14
Thank you for your time, I tried however you said but couldn't able to success. Got the solution in another comment. :) – Sandeep sandy Feb 01 '17 at 13:42

score 0 · Answer 3 · answered Jan 31 '17 at 19:47

As the location is an array of objects in your schema, you can't exclude a particular object from the result. You can exclude the whole location field from the result. However, you have an option to run aggregation on your collection.

db.sample.aggregate([
     {
        "$match" :{"_id":1}
     }, 
     {
        "$unwind" :"$locations"
     },
     {
        "$match" :{
           "locations.vname":{"$ne": "vij"}
         }
     }
    ])

This will return data in this form.

{ "_id" : 1, "locations" : { "vname" : "edd", "distr" : "prakasam" } }
{ "_id" : 1, "locations" : { "vname" : "kakani", "distr" : "guntur" } }

This is fine, But I need the output as mentioned in the post. That too "locations" field type is getting changed rather than array it is becoming an object/document. Could you help to get in that format. Thankyou. — Sandeep sandy, Jan 31 '17 at 19:57

How to retrieve the all documents of an array except one document which contains field of a particular value in MongoDB?

3 Answers3