Welcome to my 3 part series which will be all about table calculations. The first will cover the introduction to table calculations, the second will clarify the order at which the calcualtions take place and finally the third will begin to highlight more advanced table calcualtions.
Table calculations are computations that can be added to tables or charts that are already made, allowing secondary questions to be asked about the same data set. In this blog we will be focussing on how to implement quick table calculations and how the most common ones can enhance potential analysis. These can be accessed by right clicking the necessary field, then selecting quick table calculations.
When should we use them?
Table calculations differ from normal calculations (calculated fields) in the following ways:
Regular calculations:
- Exist independently from a view.
- Can be used throughout a workbook.
Table calculations:
- Table calculations depend upon the data in the view.
- Created using an existing table or data view.
Table calculations have different functions and depending on the aim of what you are trying to do will determine which one you should use. Here is a brief overview of some of the most commonly used quick table calculations:
- Running Total- For each mark in the view Tableau can calculate the cumulative sum, average or replace the value with the minimum or the maximum.
- Difference & Percentage Difference- Calculated the difference in value compared to another. Some of the examples could include previous, first or last of a given time frame. Depending on which table calculation you choose determines whether this value is a percentage or a regular number.
- Percent of Total- Calculates the proportion that the individual mark contributes to the overall total.
- Rank- Assigns values to each mark depending on the ascending or descending order it is placed.
My next blog will cover the order at which table calculations are computed.