Book Image

SQL for Data Analytics - Third Edition

By : Jun Shan, Matt Goldwasser, Upom Malik, Benjamin Johnston
Book Image

SQL for Data Analytics - Third Edition

By: Jun Shan, Matt Goldwasser, Upom Malik, Benjamin Johnston

Overview of this book

Every day, businesses operate around the clock, and a huge amount of data is generated at a rapid pace. This book helps you analyze this data and identify key patterns and behaviors that can help you and your business understand your customers at a deep, fundamental level. SQL for Data Analytics, Third Edition is a great way to get started with data analysis, showing how to effectively sort and process information from raw data, even without any prior experience. You will begin by learning how to form hypotheses and generate descriptive statistics that can provide key insights into your existing data. As you progress, you will learn how to write SQL queries to aggregate, calculate, and combine SQL data from sources outside of your current dataset. You will also discover how to work with advanced data types, like JSON. By exploring advanced techniques, such as geospatial analysis and text analysis, you will be able to understand your business at a deeper level. Finally, the book lets you in on the secret to getting information faster and more effectively by using advanced techniques like profiling and automation. By the end of this book, you will be proficient in the efficient application of SQL techniques in everyday business scenarios and looking at data with the critical eye of analytics professional.
Table of Contents (11 chapters)
9. Using SQL to Uncover the Truth: A Case Study


In Chapter 7, Analytics Using Complex Data Types, you learned the necessary skills to effectively analyze data within a SQL database. In this chapter, you will turn your attention to the efficiency of this analysis, investigating how you can increase the performance of SQL queries. Efficiency and performance are key components of data analytics. Without considering these factors, physical constraints, such as time and processing power, can significantly affect the outcome of an analysis.

In this chapter, you will first learn the different ways PostgreSQL performs query planning, in which the PostgreSQL database evaluates the SQL statement and underlying physical implementation and decides how to execute this SQL. You will learn the most basic way of retrieving data, which is scanning by sequence. You will then learn the concept of an index and the two most common indexes in PostgreSQL, the B-tree index and the hash index. From there, you will learn how to kill long...