Can anyone help.
I have a table which contains a list of bugs. Each has a creation date (creation_ts), severity (bug_severity), status (bug_status)
I need to be able to work out the average time in days it takes to clear the bugs based upon severity.
Splitting the answers in to severity is not a problem, neither is finding the status but I have no idea on how to code the average time between the creation and say a now timestamp. Creation is in normal SQL format.

Any help would be great, I have only been at SQL for a week.