Question

This is what I would like to achieve:

One with details of expenses, ie

• Food A $50
• Grocery A $20
• Grocery B $50

One with the total Expense:

• Groceries = $70

I have already linked them up via relations, and selected rollups for the amount.
The value returned on my total expense is zero.

Any idea why?

Answer 1

Not sure how you have the structure in Notion and that is the most important thing.

Here is how the structure should be.

You need 2 databases, one for expenses and one for the categories.
Relate both databases.
When you add a new expense, you select the category from the relation and add a total.
Add an expenses Rollup in the categories database, pull the total from the expenses database.

Rollup Config: Relation > Expenses, Property > Total, Calculate > Sum.

That will work as you need.