Bluecoat does not recommend, or authorize, any tampering with files, or folders, in the database structure for it's Reporter product.
There is no feature, in any version of Reporter, that allows for the removal of any type of data ( grouped or singular) from the database.
The only feature that removes data out of the Reporter database, is the scheduled event that expires all data after a certain date.
If the database is corrupted in anyway, we recommend a complete re-processing of the access logs, by following these articles:
For Version 9.x