🗞 rollup

In the example below, we have a collection – "Public backlog" – with a list of tests.

With the rollup function, we can look into that collection and return all the values in the "Public Status" column. The column name is called the "key."

Bound to a columns element in the navigator, this automatically displays 3 columns because we have 3 distinct statuses:

To recap, the formula above says:

• in the array of items in my Public backlog collection,
• return the values in the column "Public Status",
• but only unique values, if a value appears many times, we don't care.

What are the benefits of the Rollup Formula?

Before the rollup formula, you would have needed to:

• add two separate collections in WeWeb – tests and statuses,
• bind the list of tests to 3 separate columns,
• add a filter on every column to filter the tests with the correct status.

Now, you can streamline the design and improve the performance of your page by styling only one column and one card element that will be repeated by the collection list.

Another huge benefit of the rollup formula is when you use it to add a filter at collection level to fetch only the data you need: