Tableau Partitions and Dimensions illustrated

Tableau Partitions and Dimensions Illustrated

A very basic set of drawings that show how dimensions values partition up your data. I find this a useful diagram to show periodically to new students of Tableau. The concept is something you get used to fairly quickly if you use Tableau a lot, but sometimes your Excel-trained brain needs to be reminded that those single numbers that appear in each cell of a table are aggregations of multiple records.

In fact, Tableau really tries to aggregate almost everything you can look at* which can be disorienting at first. 

I find this diagram reinforces the importance of dimension values at slicing up your data. The dimension values slicing your data into partitions is actually the fundamental place to start. Anything you see is Tableau's effort to aggregate whatever collection of records is in each particular combination of dimension values. There could be 1 record, multiple records, or even no records. This is weird at first. 

*(unless you have turned off aggregation altogether which is used for certain types of graphs, not on a data table view)

Tableau Order of Operations Illustrated

Tableau Order of Operations

A more complete diagram

I have scoured quite a few posts that try to map out a more complete order of operations, but I never quite found a complete diagram. So I have started to build one here. With special thanks to Joe Mako for his feedback on an early draft. 

I expect to build a much longer version of this diagram that gets deeper into the weeds a bit more, but for most Tableau problem solving, this level of detail should be helpful to devise a strategy.

The most common problem I've had to solve with an understanding of Order of Operations, is having Top N filters applied after other filters have taken place. For example, if you want to know your top 10 customers, after excluding a few states from your map, your Top N filter will be wrong as that is applied before the Dimension Filter on [state]. 
Quick Answer: If you want your dimension filter to be applied before Top N, then after you have dragged it to your filter shelf, (or Action filter first appears on your filter shelf), convert the filter into a grey Context filter. 



The second most common for me is what's often called late filtering. How to filter your view without affecting the values of your table calculations such as Running Average. Quick Answer: Filter your view using a filter on a table calculation, i.e. on an INDEX, or LOOKUP calculation. 

Welcome to the Tableau Explained blog

Hello Tableau users of all experience levels,

The purpose of this blog is to provide materials that explain Tableau concepts for people new to the program. I have a strong bias for visual explanations, and I also find it hard to learn details without a pretty clear understanding of the big picture to hang that new knowledge onto.

I am instructor of Tableau in Vancouver at BCIT, and will gradually add more and more content as I develop it.

I will try to not to make this a blog of troubleshooting specific issues people are having, except in the sense that a high level explanation could be helpful to explain the broader context of issues.

There are already plenty of excellent blogs and resources for you to post a specific technical issue. The Tableau Community Forum is among the best (and most responsive) I am aware of. I will link to specific solutions and examples of typical issues that people encounter.

Dave