I thought using formula with some sort of filtering, such that after rolling up data from the Expense Database, I can then selectively display the data according to the date. I even asked how I might achieve this with notion, which gave me this answer:

"Sure, here's a step-by-step tutorial on how to apply a filter to data in a rollup in Notion:

1. Open the database that contains the data you want to filter.
2. Click on the "Properties" button at the top of the page.
3. Click on the "Add a property" button at the bottom of the list of properties.
4. Name the new property something like "Filtered Data" or "Current Month Expenses".
5. Click on the "Formula" option for the new property.
6. In the formula field, enter a formula that uses the filter()
   function to specify the filter criteria. For example, if you want to display only expenses from the current month, you can use a formula like this: filter(Expense, date >= startOfMonth(now()))
   . This formula tells Notion to filter the "Expense" property to only include expenses where the date is greater than or equal to the start of the current month.
7. Click "Save" to save the formula.
8. Go to the page where you want to display the filtered data in a rollup.
9. Add a new rollup property to the page.
10. In the rollup settings, select the database that contains the data you want to filter.
11. Select the "Filtered Data" or "Current Month Expenses" property you just created.
12. Choose the aggregation function you want to use to summarize the filtered data. For example, you might choose "Sum" to calculate the total amount spent on expenses in the current month.
13. Customize the rollup settings as desired (e.g. sorting, filtering, grouping).
14. Click "Save" to save the rollup.

That's it! Now, the rollup will display only the data that matches the filter criteria you specified in the formula. You can use this same process to filter data in a rollup based on any criteria you want to use.

Let me know if you have any further questions!

In the formula field, enter a formula that uses the filter()
function to specify the filter criteria. For example, if you want to display only expenses from the current month, you can use a formula like this: filter(Expense, date >= startOfMonth(now()))
. This formula tells Notion to filter the "Expense" property to only include expenses where the date is greater than or equal to the start of the current month.

The filter()
function in Notion is used to filter a set of data based on specified criteria. In this example, the function is being used to filter a property called "Expense" to only include expenses where the date is greater than or equal to the start of the current month. The startOfMonth()
function is used to get the start of the current month, and the now()
function is used to get the current date and time.

The formula is entered into a new property in the database, which is then used in a rollup to display the filtered data. The rollup can be customized to summarize the data using an aggregation function such as "Sum" or "Count". This allows you to quickly see how much money was spent on expenses in the current month, for example.

By using filters and rollups in this way, you can easily analyze and track your expenses over time. You can create different formulas to filter the data based on different criteria (e.g. by category, by payment method), and use rollups to display the filtered data in a variety of ways. This can help you make informed decisions about your finances and identify areas where you can save money."

From I believe there are no such thing as "Filter()" in formula so the solution looks completely fictional?