Book Image

SQL for Data Analytics

By : Upom Malik, Matt Goldwasser, Benjamin Johnston
3 (1)
Book Image

SQL for Data Analytics

3 (1)
By: Upom Malik, Matt Goldwasser, Benjamin Johnston

Overview of this book

Understanding and finding patterns in data has become one of the most important ways to improve business decisions. If you know the basics of SQL, but don't know how to use it to gain the most effective business insights from data, this book is for you. SQL for Data Analytics helps you build the skills to move beyond basic SQL and instead learn to spot patterns and explain the logic hidden in data. You'll discover how to explore and understand data by identifying trends and unlocking deeper insights. You'll also gain experience working with different types of data in SQL, including time-series, geospatial, and text data. Finally, you'll learn how to increase your productivity with the help of profiling and automation. By the end of this book, you'll be able to use SQL in everyday business scenarios efficiently and look at data with the critical eye of an analytics professional. Please note: if you are having difficulty loading the sample datasets, there are new instructions uploaded to the GitHub repository. The link to the GitHub repository can be found in the book's preface.
Table of Contents (11 chapters)
9
9. Using SQL to Uncover the Truth – a Case Study

Date and Time Data Types for Analysis

We are all familiar with dates and times, but we don't often think about how these quantitative measures are represented. Yes, they are represented using numbers, but not with a single number. Instead, they are measured with a set of numbers, one for the year, one for the month, one for the day of the month, one for the hour, one for the minute, and so on.

What we might not realize, though, is that this is a complex representation, comprising several different components. For example, knowing the current minute without knowing the current hour is useless. Additionally, there are complex ways of interacting with dates and times, for example, different points in time can be subtracted from one another. Additionally, the current time can be represented differently depending on where you are in the world.

As a result of these intricacies, we need to take special care when working with this type of data. In fact, Postgres, like most databases...