Book Image

Learning Tableau 2020 - Fourth Edition

By : Joshua N. Milligan
Book Image

Learning Tableau 2020 - Fourth Edition

By: Joshua N. Milligan

Overview of this book

Learning Tableau strengthens your command on Tableau fundamentals and builds on advanced topics. The book starts by taking you through foundational principles of Tableau. We then demonstrate various types of connections and how to work with metadata. We teach you to use a wide variety of visualizations to analyze and communicate the data, and introduce you to calculations and parameters. We then take an in-depth look at level of detail (LOD) expressions and use them to solve complex data challenges. Up next, we show table calculations, how to extend and alter default visualizations, build an interactive dashboard, and master the art of telling stories with data. This Tableau book will introduce you to visual statistical analytics capabilities, create different types of visualizations and dynamic dashboards for rich user experiences. We then move on to maps and geospatial visualization, and the new Data Model capabilities introduced in Tableau 2020.2. You will further use Tableau Prep’s ability to clean and structure data and share the stories contained in your data. By the end of this book, you will be proficient in implementing the powerful features of Tableau 2020 for decision-making.
Table of Contents (19 chapters)
9
Visual Analytics – Trends, Clustering, Distributions, and Forecasting
17
Other Books You May Enjoy
18
Index

Using joins

A join at the physical level is a row-by-row matching of the data between tables. We'll look at some different types of joins and then consider how to leverage them in the physical layer of a data model.

Types of joins

In the physical layer, you may specify the following types of joins:

  • Inner: Only records that match the join condition from both the table on the left and the table on the right will be kept. In the following example, only three matching rows are kept in the results:

    Figure 13.12: Inner join

  • Left: All records from the table on the left will be kept. Matching records from the table on the right will have values in the resulting table, while unmatched records will contain NULL values for all fields from the table on the right. In the following example, the five rows from the left table are kept, with NULL results for any values in the right table that were not matched:

    Figure 13.13: Left join...