When you drag a measure into the view, Tableau will use its default aggregation (more info in this post), usually the sum. If you are interested in a different aggregation, you can of course go into the context menu and select a different aggregation. But I like to use as few clicks as possible, so I prefer a different way.
Instead of dragging the field into the view by pressing the left mouse button, try using the right mouse button. When you right-click and drag a measure into the view, Tableau will then ask you which aggregation you would like to utilize instead of just using the default.
The fun part is that you can do this with any type of field. Let’s say you are interested in the distinct count of Order ID (a dimension) – simply right-click and drag this dimension into the view and Tableau will prompt you to select an aggregation of your choice.
Works with date fields, as well
By far my favourite use case for this are date fields. Tableau will open up a dialog and ask which level of the date field you would like to see. Please note that Tableau sorts and even colours the options by the discrete date parts and the continuous date values – blue on top, green at the bottom.
What I love about this trick, especially using dimensions and date fields, is that you save the intermediate step where Tableau splits your view into the different discrete values of your dimension or into your years when that’s not even something you want, thus sending an unnecessary query to your data base and using computing power to create and rearrange the view in a way you did not intend as your final result. Using right-click and drag is much cleaner and faster.
As with anything in Tableau, this hack brings you the most power if you know what you want. 😉 If you are still trying things out and are uncertain about the analysis you are trying to visualize, this may not be a helpful trick for you. Still useful to know and utilize when you can.