Book Image

SQL for Data Analytics. - Third Edition

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

SQL for Data Analytics. - Third Edition

By: Jun Shan, Matt Goldwasser, Upom Malik

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
9. Using SQL to Uncover the Truth: A Case Study

Summary

In this chapter, you learned about the window functions, which generate output for a row based on its position inside the dataset or subgroups within the dataset. This is different from the simple functions you learned in Chapter 3, SQL for Data Preparation, that generates an output for a row regardless of the characteristics of the dataset, and different from the aggregate functions you learned in Chapter 4, Aggregate Functions for Data Analysis, that generates an output for all rows in a dataset or subgroups in the dataset.

You learned some of the most common window functions including COUNT, SUM, and RANK. You also learned how to construct a basic window using OVER. The output of window function depends on the current row's position in the dataset or subgroups within the dataset, which is called partition, as well as the collection of rows required by the calculation, which is called window. As such there are several keywords that may impact how the calculation...