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

What Values Are in the Columns?

The basic charting mechanisms are a good way to see the data, but what do we want to see? The rest of this chapter discusses things of interest when exploring a single table. Although this discussion is in terms of a single table, remember that SQL makes it quite easy to join tables together to make them look like a single table—so the methods apply equally well to multiple tables.

The section starts by investigating frequencies of values, using histograms, for both categorical and numeric values. It then continues to discuss interesting measures (statistics) on columns. Finally, it shows how to gather all these statistics in one rather complex query.

Histograms

A histogram is a chart—usually a column chart—that shows the distribution of values in a column. For instance, the following query calculates the number of orders and population in each state, answering the question: What is the distribution of orders by state and how is this...