The Rollup allows you to perform a calculation on an entire column or a Relation. The most basic computation for the rollup is Count.
Column or Relation Source
For example, the app below has a list of people who all have tasks. The Tasks column is a Relation that pulls in every task assigned to each individual person. You can then create a Rollup Column that counts the total number of tasks for each person.
Adding a Rollup Column
In the Data Editor, open the table you want to edit.
Add a new column by clicking the plus (+) symbol to the right of the table.
New columns added with the plus button will always appear on the right. If you'd like to add a column somewhere else in your data, you can select the dropdown menu on an existing column and choose Add column right. You can also click and drag columns to rearrange them.
Name the column.
For Type, search for Rollup or navigate to Computed -> Rollup.
Choose which existing column or Relation you want to perform your calculation on.
Choose which calculation you want to perform.
Specify the precision in decimal points for your calculation, as well as if you want to use a group separator or add units to the calculation.
Select Done, and you will immediately see your calculations fill the column.
Calculations
The Rollup Column can perform different calculations based on the data it finds in the column or relation you select.
Numbers
The Rollup column can perform calculations such as Count, Count Unique, Sum, Average, Range, Minimum, and Maximum when applied to a column that contains numerical values.
Dates
The Rollup column can perform calculations such as Count, Count Unique, Earliest, and Latest when applied to a column that contains date values.
Boolean
The Rollup column can perform calculations such as Count, Count Unique, Count True, Count False, All True, and Some True when applied to a Boolean column.
Text
The Rollup column can perform calculations such as Count or Count Unique when applied to a Text Column.