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Data Analysis Using SQL and Excel

Data Analysis Using SQL and Excel - Second Edition

By : Gordon S. S. Linoff
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Data Analysis Using SQL and Excel

Data Analysis Using SQL and Excel

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)
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1
Foreword
17
EULA

Counting Active Customers by Day

Determining the number of active customers as of the database cut-off date is easy, by simply counting those whose status code indicates that they are active. This section extends this simple counting mechanism to historical time periods, by progressing from counting the active customers on any given day in the past, to counting active customers on all days, and finally, to breaking customers into tenure groups and counting the sizes of those groups on any given day.

How Many Customers on a Given Day?

On a given day in the past, customers who are active have two characteristics:

  • They started on or before the given day.
  • They stopped (if at all) after the given day.

The following query answers the question: How many subscriptions customers were active on Valentine’s Day in 2005?

SELECT COUNT(*)
FROM Subscribers
WHERE StartDate <= '2005-02-14' AND
      (StopDate > '2005-02-14' OR StopDate IS NULL)

The WHERE clause implements...

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Data Analysis Using SQL and Excel
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