Understanding Table Calculations
Table calculations are one of the advanced levels of calculations available in Tableau. They are also one of the most powerful features of Tableau. The reason for calling them Table Calculations is because we can define the scope and direction of the calculation based on the table/view.
To elaborate this point further, let's take a look at an example. See the following screenshot:
The preceding screenshot shows the value of three products sold across three zones. The information is arranged in a crosstab manner where the zones are placed in the columns and products are placed in the rows. Also shown are the Row Totals, that is, totals for each product across all the zones and Column Totals, that is, totals for each zone across all the products and finally we also have the Grand Total, which is the total for the entire view, that is, across all products and across all the zones.
Now, if we want to show percentages instead of just looking at the absolute numbers...