## What is the Filter formula?

The **Filter** formula allows you to tell Coda exactly what part of your tables you want to work with. You can use this in tables and canvas both. Let's see how this looks in action:

**Let's calculate the number of produce items with a canvas formula:**

`[Groceries].Filter(Department="Produce").Count()`

**What if we want to create a list of these items? **

`[Groceries].Filter(Department="Produce").Item.BulletedList()`

## Connecting tables with the Filter formula

You can also connect table data together using a combination of the **Filter** and **thisRow** formulas. This common pattern is also known as a reverse lookup, and you can read all about it here.