[Q] date-time substraction for hours

How about adding date_time_out to Hist_visitors table ! Scott }From: Saqib Mausoof <ssmaus@ccmail.monsanto.com> }Subject: [Q] date-time substraction for hours }Date: Thu, 04 Apr 1996 16:23:57 -0600 }Reply-To: Saqib Mausoof <ssmaus@ccmail.monsanto.com> }Organization: Monsanto Company }Sender: informix-list-owner@rmy.emory.edu }To: informix-list@rmy.emory.edu }X-Informix-List-To: informix-distr@fourgen.com }X-Informix-List-Id: <news.22818> } }I need to know if there is a way to do the following in SQL. } }I have a historical database for visitors. Every time an entry is made to the system, }the following fields are inserted into my Hist_visitors table, }lname, fname, vendor, date_time_in, status }Lennon, John, Beatles, 1996-03-01 10:41 PM, IN }and on exiting the site }Lennon, John, Beatles, 1996-03-02 2:30 AM, OUT } }My question is for finding out the number of man hours spend by visitors inside our }site - for every day, allowing for repeat visitors. I have a couple of ideas but }nothing concrete. If someone has done anything like this before I would love to hear }their suggestions. } } } }-- }Saqib Mausoof }-------------------------------------------------------------------- }I have a hard enough time speaking for myself, so speaking on behalf }of my employer is out of the question. } }