The OneNumber Blog — OneNumber

Tableau Education and Consulting Experts

All in Tableau Prep

Apr 23
Apr 23 How to Create Multi-Row Formulas in Tableau Prep (Difference From)

One of the most powerful, underrated features in Tableau Prep is the Difference From or "Multi-Row Formula" function. It allows you to calculate the difference in values between rows of data. This is useful when you need to calculate the time elapsed between dates or the general difference in values (e.g. dollars, counts, temperatures) from one row to the next.

This kind of calculation is only available in Tableau Desktop with a Table Calculation which is limiting because Table Calculations can only execute against data that's present in a worksheet. Pre-calculating differences in the underlying data can be a game-changer!

If you're looking to harness the power of SQL's LOOKUP/PARTITION in Tableau Prep, look no further! Check out this video for a full breakdown.

Sep 18
Sep 18 How to Union Tables in Tableau Prep

Tableau Prep, Data

When you union tables in Tableau, you append two tables of data vertically. That means if you have two tables that are 1,000 rows each, the result of the union will be a single table that is 2,000 rows. Shared columns will align automatically, and unique columns will not.

Unions provide the ability to relate multiple tables that contain different data types of structures without worrying about granularity. Many times, fact tables that primarily consist of measures cannot be joined together because the join would lead to undesired row duplication.

Jun 19
Jun 19 Tableau Prep Join Types Explained (All 7!)

One of the primary ways we combine multiple tables of data in Tableau Prep is with joins! Joins allow us to merge multiple tables of data horizontally on a common key.

One of the things that distinguishes joins in Tableau Prep from Tableau Desktop are all the join types we can create! In Tableau Desktop, we're limited to Left, Right, Inner and Outer joins. In Tableau Prep we have those four options with the addition of Left Unmatched, Right Matched and All Unmatched. Those unmatched join types provide greater flexibility to create customized workflows and identify values which did not match in our join clause.

Apr 24
Apr 24 Label First and Last Points Only in a Tableau Graph

Do you want to label just the first and last point in a graph in Tableau? For a line graph, that's simply a couple clicks away. But for a bar chart or any other type of graph, it might be a bit more involved.

Our go-to method for labeling just the first and last points is to write a table calculation utilizing the FIRST() and LAST() functions and to drop that on the label tab in the Marks card.

Want to learn how? Check out this video!

Mar 27
Mar 27 How Tableau Prep Decides Default Group Names

A fundamental component of Tableau Prep is the ability to clean messy data. One of the best ways to do that is by creating groups! However, creating groups can be confusing. How does Tableau Prep decide what to name a group? For example, if you group "Boise" and "Boise City" together into a single city name, which does Tableau Prep choose? Well, that all depends on the grouping method you select.

Automated Groups: If you use automated groups (grouping on pronunciation, common characters, etc.) it will choose the more populous value. So if there are 100 rows for "Boise" and 5 rows for "Boise City", the group name will default to "Boise".

May 17
May 17 How to Set Up a Multi-Row Formula in Tableau Prep (v 2023.1 and Earlier)

Tableau Prep is a powerful data preparation tool which allows you to do complex data transformation in a "no code" environment. No need to learn Python, SQL or R to shape your data.

While Tableau Prep has come a long ways in its first five years of existence, it's still a young tool with limitations. For example, it's not strong at crafting multi-row formulas (e.g. referencing the value from the previous row in the next row).

Feb 22
Feb 22 How to Automate a Tableau Prep Flow

Tableau Prep is a powerful tool for cleaning, structuring and preparing data for analysis in Tableau Desktop. The Tableau Prep Builder software provides the ability to create data workflows which can be run manually. That's fine when data is updated infrequently, but it doesn't work well when data needs to be refreshed every day or every hour.

Sep 8
Sep 8 Why aren't I seeing all my data in Tableau Prep?

Tableau Prep is a powerful tool for cleaning and shaping data. One of its weaknesses is that it can be slow on a desktop computer. There are a number of reasons for that (computer memory limitations, size of data source, complexity of steps, etc.). One of the ways that Tableau Prep conducts these performance issues is to sample your data automatically.

Jun 28
Jun 28 How to Prepare (Structure) Data for Tableau - Webinar Recording

Data, Tableau Prep

Are you having trouble getting your data to work in Tableau the way you want? Join us to learn how to prepare data for analysis in Tableau!

You can find a thousand tutorials on how to use Tableau, but they're all worthless until your data is structured for analysis in the format that Tableau likes. Don't get stuck in your analysis journey because Tableau doesn't like your data.

6 data formats to avoid, 8 key rules for structuring data, and 1 video you can't miss. Check out the recording to learn about the key concepts you can utilize to prepare for your data for Tableau.

Oct 7
Oct 7 Identify and Modify Grouped Values in Tableau Prep

Tableau Prep, Data

The numerous grouping options in Tableau Prep are one of the best parts of the tool. In addition to manual grouping, you can group based on common characters, pronunciation and spelling. However, scrolling through existing values and grouped values to determine if the groups which Tableau Prep created were a good fit can be cumbersome.

Aug 26
Aug 26 How To Unpivot (Transpose) in Tableau Prep - Using the New Rank Feature

Tableau Prep, Data

No! This post is not a mistake. It really is our third blog post in the last three years detailing how to transpose values in Tableau Prep. The tool is rapidly evolving, and the good new is that the process of transposing values is becoming more seamless each time.

Jan 2
Jan 2 How to Deal With Multi-Response Survey Data in Tableau Prep

When you are working with survey data, you will occasionally come across situations where survey questions were multiple choice and those multiple choices responses are comma-delimited in a single cell.

Nov 1
Nov 1 Tableau Prep File Types

Tableau Prep is a new desktop application (released spring, 2018) provided by Tableau to assist with complex data preparation.

Jul 26
Jul 26 How to Transpose Multiple Data Fields Using Tableau Prep

In June, 2018 I wrote a blog post about three things Tableau Prep couldn’t do. One of those was the ability to transpose (unpivot) data. That is no longer the case. Tableau Prep Builder now gives you the capability to transpose rows of data into columns. Let’s look at an example.

Apr 5
Apr 5 What I Learned About Working with Shapefiles in Tableau

Tableau Prep, Tableau Dashboards, Tableau How-Tos

I grew up in the Issaquah/Sammamish area of Washington State about 30 (depending on traffic 60) minutes east Seattle. When I was growing up there in the 1990s and 2000s I remember hearing comments from a lot of people that, “this area has the highest amount of high school students per capita anywhere in the state.”

Jan 25
Jan 25 Preparing Survey Data with Tableau Prep - Webinar Recording

Preparing survey data for analysis in a data visualization tool is notoriously difficult. It's not as simple as being able to perform a single pivot or filter.