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  • Book Overview & Buying Hadoop MapReduce v2 Cookbook - Second Edition: RAW
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Hadoop MapReduce v2 Cookbook - Second Edition: RAW

Hadoop MapReduce v2 Cookbook - Second Edition: RAW - Second Edition

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Hadoop MapReduce v2 Cookbook - Second Edition: RAW

Hadoop MapReduce v2 Cookbook - Second Edition: RAW

4.4 (7)

Overview of this book

If you are a Big Data enthusiast and wish to use Hadoop v2 to solve your problems, then this book is for you. This book is for Java programmers with little to moderate knowledge of Hadoop MapReduce. This is also a one-stop reference for developers and system admins who want to quickly get up to speed with using Hadoop v2. It would be helpful to have a basic knowledge of software development using Java and a basic working knowledge of Linux.
Table of Contents (12 chapters)
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11
Index

Performing a join with Hive


This recipe will guide you on how to use Hive to perform a join across two datasets. The first dataset is the book details dataset of the Book-Crossing database and the second dataset is the reviewer ratings for those books. This recipe will use Hive to find the authors with the most number of ratings of more than 3 stars.

Getting ready

Follow the previous Hive batch mode – using a query file recipe.

How to do it...

This section demonstrates how to perform a join using Hive. Proceed with the following steps:

  1. Start the Hive CLI and use the Book-Crossing database:

    $ hive
    hive > USE bookcrossing;
    
  2. Create the books and book ratings tables by executing the create-book-crossing.hql Hive query file after referring to the previous Hive batch mode commands using a query file recipe. Use the following commands to verify the existence of those tables in the Book-Crossing database:

    hive > SELECT * FROM books LIMIT 10;
    ….
    hive > SELECT * FROM RATINGS LIMIT 10;
    ….
    
  3. Now, we...

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Hadoop MapReduce v2 Cookbook - Second Edition: RAW
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