Now, I should probably be a good Planet MySQLer and check the MySQL Forge at http://forge.mysql.com, but Dean Swift’s “mystery festive stored procedure” linked at http://deepselect.blogspot.com/2006/12/merry-christmas.html is a pretty good interview question for a candidate. I would include the hint that it’s a Christmasy stored procedure.
I laughed out loud when I figured it out. I didn’t actually run it, but read the stored procedure to see if I could puzzle it out. And so I did. It took a few minutes, and I had to copy and paste it to a buffer that used word wrap and format it properly.
But this will show how good someone is under pressure. If you give it to them and walk away, there will be less pressure. Either way, you’ll see their reaction too — if it’s “ha ha very funny who cares?” or if it’s, “that’s pure genius!” or if it’s a big groan or hearty laugh, you’ll see a person’s personality and how they might fit in with the team.