Tag Archives: compute using

At the Level – Unlocking the Mystery Part 2: Rank Functions

Many moons ago I did a first post exploring the non-obvious logic of the most secretive of Tableau table calculation configuration options: At the Level. A few weeks ago I was inspired by a question over email to dive back in, this post explores At the Level for the five rank functions: RANK(), RANK_DENSE(), RANK_MODIFIED(), RANK_UNIQUE(), and RANK_PERCENTILE(). The rank functions add a level of indirection to the already complicated behavior of At the Level and I don’t have any particular use cases, so…

If you are like me and won’t rest until you understand every detail of Tableau’s functionality, then this post is for you. Otherwise you may find this post unhelpful and/or confusing due to extreme table calculation geekery. You have been warned.

The particular challenge with ordinal functions like INDEX(), FIRST(), and the rank functions is that we absolutely have to understand how addressing and partitioning works in Tableau, and then we tack onto that an understanding of how the calculations work, and finally we can add on how At the Level works. For the first part, I suggest you read the Part 1 post on At the Level, it goes into some detail on addressing and partitioning. To understand the rank functions here’s the Tableau manual for table calculations (scroll down to the Rank functions section). Finally, read on for how At the Level works for rank functions.

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