Group by mongo Shell

Question

I have collection where each document has user related details. userid:1001,abc:1 userid:1001,abc:9 userid:1002,abc:1 userid:1001,abc:3

Something like this. I wanted to get count of userId which has maximum occurances. I need to do this on Mongo shell.

Any ideas?

Ofcourse. this is not a straightforward answer. Hence posted it here. I want group by + max count. — rl99, Sep 23 '13 at 17:42
This is the most basic example of aggregation always mentioned in the docs and numerous questions on this site. — Sammaye, Sep 23 '13 at 18:55
Yes. I get it now , how I can use aggregation for this use case. — rl99, Sep 23 '13 at 21:03

score 2 · Accepted Answer · answered Sep 20 '13 at 17:07

2

Check the aggregation framework of mongo. For the answer you can use $group operator to group by userid and sorting them based count. Something like this:

Suppose collection name is test:

db.test.aggregate([{"$group":{"_id":"$userid","occurence":{"$sum":1}}},{$sort:{"occurence":-1}}])

answered Sep 20 '13 at 17:07

fgakk

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I think the version of mongo I have does not support aggregate. – rl99 Sep 23 '13 at 18:23

Group by mongo Shell

1 Answers1