Question: My scenario is tracking employees who complete online training. I capture their name, id, class taken, and date. Any employee is free to take a plethora of different courses and they could take them all on the same day if they want. What I am trying to do is see if any employee has taken any course more than once in any given day?

Answer:

Highlight-taken-courses-more-than-once-in-any-given-day-in-excel

Conditional formatting formula:

=SUM(COUNTIF($A2, $A$2:$A$35)*COUNTIF($B2, $B$2:$B$35)*COUNTIF($C2, $C$2:$C$35))>1

Download excel sample file for this tutorial.
Highlight duplicate online classes using conditional formatting
(Excel 97-2003 Workbook *.xls)

Functions in this article:

COUNTIF(range,criteria)
Counts the number of cells within a range that meet the given condition

SUM(number1,[number2],)
Adds all the numbers in a range of cells