DATE_FORMAT function if your friend in this case. You can format the date as a specific string format.
You can find more information on the codes used here: https://www.w3schools.com/sql/func_mysql_date_format.asp
DATE_FORMAT(`Date`, '%Y-%m-%d %H:%i:%s')
@Devin_Garrison As a side note, if you just need those timestamps to show up in a card in 24 hour format, it actually displays them that way without needing to do anything. I tried it out with a couple of timestamp columns in my data and it displayed everything in 24 hour format. It seems that when you look at them at the dataset level, Domo displays them in 12 hour format.