Tableau - Combining two column Values into a dropdown list

Question

In my Tableau table, there are two columns as below,

Column1         
========           
A
B
C

Column2
========
D
E
F

I want to combine the values from both the columns and show in a Single dropdown list (Filter).

Result Dropdown
===============
A
B
C
D
E
F

Can anyone help me to do this ? Thanks in advance.

Answer 1

If the data won't refresh very frequently, You can create a parameter using the above two columns and use it as a dropdown which will work on the visualizations using a calculated field.

In the below screenshots, i have added the country as well as the states in a single dropdown as an example for your reference.

Once you have the parameter created, you can slice and dice your visualizations by creating a calculated field and use it in rows or columns or in filter for your visualizations.

Answer 2

You basically have 2 options:

1. Go to the Data Source tab, select the columns, right click and select Pivot. But, if you have more columns, you might get unwanted results.

2. Do the UNION/Merge directly in the data source. If the data is coming from a query, use UNION. If it's a file, try combining the data in the file and then load it in Tableau.