I can only help you with specific dates only,
Purge events from the database.
All events older than the specified date will be removed from the database. For example, if reporting information for the last three months is required, then specify a date three months in the past.
Type the command below at the 1> prompt and press ENTER:
delete from EPOEvents where DetectedUTC < 'YYYY-MM-DD'
Ensure that the format of the date is year-month-day. Example: 2007-12-01 for December 1, 2007.
At the 2> prompt, type go and press ENTER.
NOTE: This command can take more than an hour to complete, depending on the number of events to purge. If this completes successfully, you see a message indicating the number of affected rows
May be some one else would jumpin and give you required command .