How to find the max value across multiple columns?

Summary:

Staff can enter up to 6 qualifications in separate flexfields in the UI.

We have a requirement to report on the highest value code entered for each employee. As you will see from the image below, the highest code could be in any order across the 6 fields as there are no entry restrictions in the UI.

How can we identify the highest value code for each employee across the multiple columns?

Content (required):

Version (include the version you are using, if applicable):

23A

Code Snippet (add any code snippets that support your topic, if applicable):