Book Image

Data Analysis Using SQL and Excel - Second Edition

By : Gordon S. S. Linoff
Book Image

Data Analysis Using SQL and Excel - Second Edition

By: Gordon S. S. Linoff

Overview of this book

Data Analysis Using SQL and Excel, 2nd Edition shows you how to leverage the two most popular tools for data query and analysis—SQL and Excel—to perform sophisticated data analysis without the need for complex and expensive data mining tools. Written by a leading expert on business data mining, this book shows you how to extract useful business information from relational databases. You'll learn the fundamental techniques before moving into the "where" and "why" of each analysis, and then learn how to design and perform these analyses using SQL and Excel. Examples include SQL and Excel code, and the appendix shows how non-standard constructs are implemented in other major databases, including Oracle and IBM DB2/UDB. The companion website includes datasets and Excel spreadsheets, and the book provides hints, warnings, and technical asides to help you every step of the way. Data Analysis Using SQL and Excel, 2nd Edition shows you how to perform a wide range of sophisticated analyses using these simple tools, sparing you the significant expense of proprietary data mining tools like SAS.
Table of Contents (18 chapters)
Free Chapter
1
Foreword
17
EULA

CHAPTER 5
It’s a Matter of Time

Along with geography, time is a critical dimension describing customers and businesses. This chapter introduces dates and times as tools for understanding customers. This is a broad topic. The next two chapters extend these ideas by introducing survival analysis, the branch of statistics also known as time-to-event analysis.

This chapter approaches time from several different vantage points. One perspective is the values that represent dates and times, the years, months, days, hours, and minutes. Another is when things happen, along with ways to visualize changes over time and year-over-year comparisons. Yet another perspective is duration, the difference between two dates, and even how durations change over time.

The two datasets used for examples—purchases and subscribers—have date stamps accurate to the day, rather than time stamps accurate to the minute, second, or fraction of a second. This is not an accident. For many business...