Book Image

Apache Hive Essentials - Second Edition

By : Dayong Du
Book Image

Apache Hive Essentials - Second Edition

By: Dayong Du

Overview of this book

In this book, we prepare you for your journey into big data by frstly introducing you to backgrounds in the big data domain, alongwith the process of setting up and getting familiar with your Hive working environment. Next, the book guides you through discovering and transforming the values of big data with the help of examples. It also hones your skills in using the Hive language in an effcient manner. Toward the end, the book focuses on advanced topics, such as performance, security, and extensions in Hive, which will guide you on exciting adventures on this worthwhile big data journey. By the end of the book, you will be familiar with Hive and able to work effeciently to find solutions to big data problems
Table of Contents (12 chapters)

Functions

To further manipulate data, we can also use operators, expressions, and functions in HQL to transform data. The Hive wiki (https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF) offers specifications for all supported expressions and functions, so we do not want to repeat all of them here, except a few important tips in this chapter.

Hive has defined relational operators, arithmetic operators, logical operators, complex type operators, and complex type constructors. For relational, arithmetic, and logical operators, they are similar to standard operators in SQL/Java. For operators on a complex data type, we have already introduced them in the Understanding Hive data types Section in Chapter 3, Data Definition and Description, as well as the example of inserting data into dynamic partitions earlier in this chapter. Functions in HQL are categorized as follows...