Sort column other then with the columns content

I am building a persons database for on my website.
In it I wish to show the persons birthdate in the following format: "01 January 1836"
When sorting the table using the column "birthdate" I wish however to sort using the date in a different format: "1836.01.01" (ie YY-MM-DD)

Is this possible?

I had the idea to add an alternate column to my db-file in which I add the date in the preferred format (YY-MM-DD).
Then, when viewing the data on my website, I have the column "birthdate":
1. showing the date from the db-column: 01 January 1836
2. sort the table using the date from the (different) column: 1836.01.01


Is this possible? or is there another way to achieve what I seek?

thanks for the help