All by Eric Parker

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

Eric Parker
Tableau Prep

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.

How to Build a Sales Funnel in Tableau

Eric Parker
Design, Tableau Dashboards

Want to learn how to build a sales funnel in Tableau? You've come to the right place! Most funnels are hard to interpret because they deal with size disproportion issues. The classic upside-down triangle visual likely isn't the best way for you to represent funnel data for your users.

We've built funnels for dozens of clients over the last decade and have distilled our learnings into this video! Check it out for tips on writing calculations, building a funnel visual, formatting effectively and compiling it all into a meaningful dashboard.

How to Build Multi-Fact Relationship Data Models in Tableau

Eric Parker
Tableau Relationships, Data

One of the biggest areas of technical advancement in Tableau Desktop over the last several years is the ability to model complex data sources. Relationships first debuted in 2020 but were only usable for simple data models because you could only use a single fact table as a base table.

In 2024, Tableau updated the Relationship builder to allow for multiple-fact tables and shared dimension tables. This ability is invaluable in complex analyses that leverage numerous tables.

Overlay Custom Time Periods in a Tableau Line Graph

Eric Parker
Tableau Calculations, Tableau Dates

Comparing one time period to another is a common use case in Tableau. In our experience, one of the best ways to do that is to overlay one on top of the other. The question is, how do you do that dynamically for both a current and comparison period?

Check out this video for one of our favorite homegrown solutions where you create a custom date field and a custom value label which allows you to overlay two time periods for comparison!

Tableau Dashboard URL Actions Explained

Eric Parker
Tableau Dashboards

How do Tableau URL Actions work? Let's dive into how they work, what they can do and some creative ways you can customize them.

URL Actions in Tableau provide the ability to generate open a tab in a browser based on a user selection. There are loads of ways to set them up too. You can reference a full URL field from your data source, you can append a field to the end of a static URL slug, heck you can even generate a form email from within Tableau using fields in your data source!

How to Union Tables in Tableau Prep

Eric Parker
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.

Custom Date Filter for Aggregated and Non-Aggregated Measures in Tableau

Eric Parker
Tableau Dates

Creating custom date filters in Tableau takes some creativity and ingenuity. They can be especially tricky when they are used to control both aggregated and non-aggregated measures. Tableau is particular about how aggregated formulas are written.

If you want to create a custom date filter in Tableau that controls both aggregated and non-aggregated measures but you're struggling to write the formulas without errors, check out this video for some helpful tips!

Dynamic Start and End Date Filter in Tableau

Eric Parker
Tableau Dates

One of my favorite and most-often used date filters in Tableau is a range of dates with dynamic start and end dates.

For example, you choose a range of dates (last 7 days, last 14 days, last 30 days, etc.) and then create dynamic start and end date filters that meet that criteria. This is a great way to provide a pre-selected filter range for your users but still give them ultimate control over the exact date range they want to see.

Tableau Prep Join Types Explained (All 7!)

Eric Parker
Tableau Prep

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.

How to Sort Stacked Bars With a Selection in Tableau

Eric Parker
Tableau Sets, Tableau How-Tos

Stacked bar charts are a brilliant visual for displaying how individual segments contribute to the overall value of a category, and how a category ranks in relation to other categories. Like all data visualizations however, it has some weaknesses.

One of the biggest weaknesses of a stacked bar chart is that it's hard to compare bar segments when they don't have a shared baseline. Comparing the first bar segment is straightforward, but comparing the 3rd or 5th segment is cumbersome.

Label First and Last Points Only in a Tableau Graph

Eric Parker
Tableau Prep

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!

How Tableau Prep Decides Default Group Names

Eric Parker
Tableau Prep

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".

How to Build a Dynamic Date Range Filter in Tableau

Eric Parker
Tableau Dates

Do you want to build a customizable, dynamic date range filter in Tableau?

For example, imagine you want the filter to default to the last 14 days ending with today's date, but you'd like your user to be able to adjust the end date and number of days in that filter.

That combination of functionality is not available out-of-the-box in Tableau, but with some creativity, parameters and calculations, it's possible!

Dynamic Titles for Tableau Dashboards

Eric Parker
Tableau Dashboards

One of the primary purposes of a dashboard title is to provide context for users. It should give them a sense of what they are looking at, and what they are looking for.

My favorite way to add value to a dashboard title is to have it reflect filter selections. For example instead of saying "How is our hospital system performing?" it could say "How is Trinity Northern performing?" when the dashboard is filtered to a single hospital.

Filter Selected and Comparison Periods at the Same Time in Tableau

Eric Parker
Tableau Dashboards, Tableau Dates

Filtering on a date range in Tableau is pretty straightforward, right? But how about if you want to filter on that date range AND you want a comparison date range filtered at the same time? That's trickier.

For example, you set a filter from January 1st to March 15th 2024 and you want a comparison period of January 1st to March 15th 2023 to automatically be set, how do you do that?

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