Similar to SQL, HQL supports both implicit and explicit type conversion. Primitive-type conversion from a narrow to a wider type is known as implicit conversion. However, the reverse conversion is not allowed. All the integral numeric types, FLOAT, and STRING can be implicitly converted to DOUBLE, and TINYINT, SMALLINT, and INT can all be converted to FLOAT. BOOLEAN types cannot be converted to any other type. There is a data type cross-table describing the allowed implicit conversion between every two types, which can be found at https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Types. Explicit-type conversion uses the CAST function with the CAST(value as TYPE) syntax. For example, CAST('100' as INT) will convert the 100 string to the 100 integer value. If the cast fails, such as CAST('INT' as INT), the function returns...
Apache Hive Essentials - Second Edition
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Apache Hive Essentials - Second Edition
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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
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Current Title:
Apache Hive Essentials - Second Edition
Table of Contents (12 chapters)
Preface
Free Chapter
Overview of Big Data and Hive
Setting Up the Hive Environment
Data Definition and Description
Data Correlation and Scope
Data Manipulation
Data Aggregation and Sampling
Performance Considerations
Extensibility Considerations
Security Considerations
Working with Other Tools
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Customer Reviews