## What is the Filter formula?

The **Filter** formula allows you to tell Coda exactly what part of your tables you want to work with. Like with all formulas in Coda, you can build it anywhere by typing "=".

After the = sign, you'll type the table name then ".Filter". Note, the "." is critical. Let's take a look at an example:

**Calculate the number of produce items:**

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

**2. Calculate the number of produce items with a stock of less than 5:**

`=[Groceries].Filter(Department=Produce AND Quantity<5).Count()`

**3. Create a bulleted list of the produce items with a stock of less than 5:**

`=[Groceries].Filter(Department=Produce AND Quantity<5).BulletedList()`

## Connecting tables with the Filter formula

You can also connect table data together using a combination of the **Filter** and **thisRow** formulas. For example, maybe I want a summary table that shows the amount of items we have in each grocery department.

To begin, I would create a new table with each department listed in rows. Then, I would change the column format in our core grocery table to be a Lookup:

Then, I can add the following formula to my summary table:

`=[Groceries].Filter(Department=thisRow).Count()`

This formula tells Coda to look at the row in the summary table, and filter the other table by that value:

As a shortcut, once you have lookup columns, you can quickly add relevant columns about the source information when you click the + sign to add a new column: