Tableau: Control Date Level with Parameters (Year, Month, Quarter)

Step 1:

Build a dual axis chart using [Date], [Quantity], and [Sales]. The result will be a combined bar and line chart.

Step 2:

Create a string parameter with these options. year, quarter, month. Make sure they are not capitalized. You can set an alias with a capital letter for display purposes.

Step 3:

Create this calculated field to serve as the date that is controlled by the parameter.