I agree with Dave62 on this, a probation period of 6 months. That's what my company has and it has worked for us, some mistakes but that can be expected. Nothing you do will guarantee a 100% success. I would say looking at someone's work history would help weed out some bad people. If you haven't stayed at a job for more than a year or two would be a giant red flag to me. Either you couldn't do the job or you are only interested in 'moving up'. And what guarantee will I have that you will stay here for very long.

With the easy of, coming to this site:-), and other online sources to find answers to help you solve any problem, to dismiss someone just because they can't memorize some commands for your test seems pointless.

I'm no DBA, but I'm sure I could find the answers I need if I had to do it. Doesn't mean it would be the best or fastest way to do it and it may take me more time. But it could be done. The willingness to learn is key. IMHO