MongoDB Tutorial 4 Map Reduce Finalize Group

Get the Code Here :
Best MongoDB Book :

I received a bunch of questions about using Map Reduce in MongoDB, so here I provide a bunch of examples. First I’ll cover Map Reduce using straight JavaScript. Then we’ll cover increasingly complex MongoDB Map Reduce queries. Then finally I’ll cover using Group and Distinct.






22 responses to “MongoDB Tutorial 4 Map Reduce Finalize Group”

  1. Vasanth D Avatar

    Hi Derek .. Wonderful .. Thanks a lot.

  2. Croz 1007 Avatar

    So, these Map Reduce functions are creating a new DB to hold the output? Is that common practice with MongoDB? Is that how it should be handled if you had different document types or models (Students, Assignments, etc.)?

  3. I like sandwiches Avatar

    "I have a lot to do, so let's get into it!"
    should be every programmer's anthem

  4. Santosh Baggam Avatar

    hi Derek, fabulous tuts.. I'd just want to learn more on MongoDb GeoIndexing.. can you upload a vid explaining various use cases.. eg: nearby store locations, Uber taxi vehicle tracking, etc.. would be a great one to watch. thanks in advance 🙂


    These are really great tutorials within such less time. Great efforts.
    Can you please show us a way to take mongodb backup and restore? And suggest any opensource admin ui similer to phpmyadmin.

  6. Ashfaq Khan Avatar

    How to export a file in mongoDB to a csv format? I've tried few commands but went in vain. Appreciate your work!

  7. Enoch Phetteplace Avatar

    OK so how do you upload a file to mongo?

  8. Vardaan Avatar

    Can you do a tutorial on storing images,videos in mongoDB.

  9. Edvinas Gurevičius Avatar

    Great videos! Would be even better if there was at least one real life application example where we could use MangoDB. Let's say – simple login system, or article class, or anything, but real, not abstract, not doesn't even need to be simple. Thank you!

  10. regulus8518 Avatar

    hi could you help with gridFS tutorial, to store images etc in mongo db please

  11. SKAnanitoS Avatar

    this tutorial was really good! the only thing I would like to mention is that it would be nice to have another video with MongoDB injection attacks and techniques that we can use to avoid them.

  12. klausvonshnytke Avatar

    I find it rather depressing that there are so few tutorials about jboss fuse. Even those on the official website are not very technical. Would you mind recording something on this subject?

  13. aro p Avatar

    ples help me, ik this is unrelated but my progress has stopped because of this. i looked everywhere on the world wide web(stackoverflow) but came out with more questions than answers

    Android development. i want to save an arraylist of custom objects after an app has exited.

    i have watched the video on it and i can save the array list if android decides to close the app, but not if the user decides to.

    how would i save an array list of custom objects to shared preferences. or is there another way entirely to save arraylists if user decides to close an app.

    i tried converting the list to a set and saving it that way but no luck.

  14. viquar ahmed Avatar

    hi derek… I hope next videos are angular js and R programming tutorials.BTW congratulations for completing Mongodb tutorials series.

  15. Phillip Drake Avatar

    Thanks for the tut!

  16. Masoud Rousta Avatar

    really nice and educational , well done

  17. brakleet Avatar

    soo why are there 4 parts? is this language hard/big?? why

  18. Piyussh Singhal Avatar

    can you plz do a CSS tutorial.

  19. AnimationMan Avatar

    Can you please do a Java game engine tutorial? Please answer!

Leave a Reply

Your email address will not be published. Required fields are marked *