SELECT COUNT(*)
FROM msdb.dbo.sysmail_allitems

SELECT *
FROM msdb.dbo.sysmail_allitems

EXEC  msdb.dbo.sysmail_delete_mailitems_sp
      @sent_before = '2012-05-10 00:00:00',
      @sent_status = 'sent'

SELECT description
FROM sysmail_event_log
ORDER BY log_date DESC

