I see... I thought it was just that easy based on the other default date columns in Calibre. And I figured that stating I had to find a code showed I knew nothing about creating a code myself. Sorry. I can sometimes get them adapted to what I want if their super simple, but generally probably less than 50/50 odds.
I knew the searching by date thing was going to be something super simple I just couldn't see, thanks for that
I'm using this information so that I can see when I last updated the metadata to the file. I understand why, but it still drives me nuts that the actual book metadata can only be manually updated. My type-A personality likes to have that information embedded in the book itself as a fail-safe, but I don't need to update every single book every time; this way I can just update the books that have had any metadata updated (read status, series correction, etc.) since it was added to Calibre (if the modification date is greater than the file modification date, the book needs updating).
Okay, I think for my purposes and skill level that having separate columns will work just fine for me, now that I know how to make it searchable by date.
Thanks for your help!