Book Image

QlikView for Developers Cookbook

By : Stephen Redmond
Book Image

QlikView for Developers Cookbook

By: Stephen Redmond

Overview of this book

QlikView has been around since 1993, but has only really taken off in recent years as a leader in the in-memory BI space and, more recently, in the data discovery area. QlikView features the ability to consolidate relevant data from multiple sources into a single application, as well as an associative data model to allow you to explore the data to a way your brain works, state-of-the-art visualizations, dashboard, analysis and reports, and mobile data access. QlikView for Developers Cookbook builds on your initial training and experiences with QlikView to help you become a better developer. This book features plenty of hands-on examples of many challenging functions. Assuming a basic understanding of QlikView development, this book provides a range of step-by-step exercises to teach you different subjects to help build your QlikView developer expertise. From advanced charting and layout to set analysis; from advanced aggregations through to scripting, performance, and security, this book will cover all the areas that you need to know about. The recipes in this book will give you a lot of the information that you need to become an excellent QlikView developer.
Table of Contents (19 chapters)
QlikView for Developers Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Handling null in numeric fields or calculations


Whether in the QlikView script or in an expression, we often have to check if a value is null (absence of value) or blank (empty string) before using it in a calculation. SQL developers will be used to the ISNULL or COALESCE function and it is useful to have an equivalent. There is an IsNull() function in QlikView, which returns a Boolean true/false. My experience is that this does not always work reliably on all platforms and, if I want a IsNull Boolean, I tend to check Len(Field)=0 or Len(Trim(Field))=0 instead. This is a little clunky to use with an If statement in an expression so I find the Alt function to be much more elegant.

Alt can take any number of parameters and will return the first one in the list that is a number. In this case, I will only use two parameters—the field to be tested and then either 0 or 1—depending on what I want the default to be.

Getting ready

Load the following script:

Alt_Example:
Load * Inline [
	Month, LocalSales...