In the analysis module of the QC there are bunch of report types that you can measure what is going on about the defects for your project. But some reports are missing. I'll describe one of the most important one.
If you want to see how much time spent for fixing a defect you have to check it's history section from the GUI. There is no way - at least i couldn't find - for taking this information from the predefined reports for all (or a group of) defects. Here is the SQL for how many hours passed for changing a defect's status (Closed and Rejected&Closed statuses are assumed to be final statuses for a defect). You can use these SQLs in the Analysis section by creating Excel Report or you may want to use them directly as a SQL statement via TOAD or you can embed them in an excel sheet.
This SQL will output the status change actions for all defects for the action that is shown in the ACTION column. For example if the ACTION column is New>Open this means TIME_ELAPSED_HOURS column shows how many hours passed until the corresponding defect status changed to "Open" from "New".
It is a good idea to create a View by using this SQL.
To get overall report and transpose from this SQL you can use following statement: