What type of errors actually happen with mySQL/PHP

[jilly]

I'm working on a web-based application using mySQL, and I've used it in the past. I've never seen a mySQL error other then something during the development process -- ie. poorly formed selects -- but once its 'working' what kind of errors are there?I've never seen an insert or select fail - can they? If the syntax is correct, why would they?I'm mostly asking this with an eye toward figuring out what to do if an error actually does occour. If an insert/update fails, do I sleep a second and try again? How about a select? How many times before just giving up?EDIT:Maybe I asked this poorly, what I'm looking for is "How should I handle mySQL errors if and when they occour?". In every sample I've ever seen its to just die -- in a public application that seems very ugly. Is it worth retrying the command in a few seconds and then giving a error to the user and emailing the admin? Or just accept that a fatal error won't get fixed.