Use column info as template I got this wild idea to fix a date format issue i've been having. 

The idea is to use column info to act as a template for the date format since mm/dd/yy can get really confusing for the database since I always use YYYY-mm-dd but my users like to mix things around.

The thing is that I have some trouble to figure out exactly how the SQL would look like.

My idea is something like this:

Tablename: USER
Col1, Col2, Col3, date_template


And the other info:

Tablename: activity
item, quantity, price, date, time


Yes, I know that it could be fixed in the code of the page but since I'm not the creator of the site I won't go into fiddle around with the code until I got some time to make a new page.
I think you will have an easier time to simply cast whatever the user throws at you to a date format that you want, to keep it all uniform. E.g. in PHP like this: date('Y-m-d', strtotime($userdate))

It can also be done in sql with convert(date, '28/09/2016'), however I think you need to specify the format. Link