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

Lookup Model for Order Size

The previous model was a lookup model for classification, both for multiple classification and binary classification. The lookup itself was along a single dimension. This section uses lookup models for estimating a real number. It starts with the very simplest case, no dimensions, and builds the model up from there.

Most Basic Example: No Dimensions

Another basic example of a lookup model is assigning an overall average value. For instance, we might ask the question: Based on purchases in 2015, what do we expect the average order size to be in 2016? The following query answers this question, by using the average of all purchases in 2015:

SELECT YEAR(o.OrderDate) as year, AVG(o.TotalPrice) as avgsize
FROM Orders o
WHERE YEAR(o.OrderDate) in (2015, 2016)
GROUP BY YEAR(o.OrderDate)
ORDER BY year

This query gives the estimate of $86.07. This is a reasonable estimate, but it is a bit off the mark because the actual average in 2016 is $113.19. The average could...