Dates are special in Tableau and require special attention. In Tableau, once a field is identified as a date, Tableau automatically creates a date hierarchy. The date field will allow you to drill down from year to quarter, to month, to day.

Dates can also either be discrete or continuous. With our Superstore dataset, lets drag our Order Date field to the Columns shelf. By default, when you drag a date over to either your column or row shelf, you will get a year, date field, blue pill. A blue pill means a date field is discrete. Which means, distinct values and this will produce a header for us.

Let’s back up and ask what really does this Order Date field look like? Below is the screenshot of Tableau showing just a few rows of data. It’s in a month-day-year format.

In our Sheet, drag Order Date to the Columns and it will look something like the following.

We got a blue pill. This means discrete. We see that Tableau created a header for us showing each year. Dates can be continuous, not discrete. This means that Tableau will show a green pill. The values will be unbroken and in a range and Tableau will therefore generate an axis for us.

If you are wanting to look at trends over a period of time, you would want to work with a continuous date. I added Sales. I changed the Tooltip to include the string USD just by clicking the Tooltip in Marks and adding the text. Easy to do. I changed the title as well.

When working with dates, your data may not have all of the information you need. You may need to create a calculated field.