Re: determining time difference between two timestamp fields.

On 25 May 2010 15:55, Bruce Gilbert <webguync@gmail.com> wrote: > Here is the situation. I have a form which sets a timestamp when a > user logs in using UPDATE in SQL. The field is called > 'login_timestamp' and is in a table called 'Candidates'. I have > another timestamp which is set when a user submits the form data into > the DB and it is called 'submit_timestamp' . What I want to do is > determine the amount of time the user takes to complete the form by > subtracting the 'login_timestamp' time form the 'submit_timestamp' > time. I am using SQL to extract the data here. > > $sql = "SELECT Responses.name,Answers,submit_timestamp,login_timestamp >           FROM Responses LEFT JOIN Candidates USING (user_id)"; > > and then to display the timestamp in readable form. > > echo "<tr><th>Completion Time:</th></tr><tr><td>" > . date('F j, Y > g:i:sa', strtotime($row["login_timestamp"])) . > "</td></tr>"; > > so I need to know how to subtract from two timestamp fields, two > different tables and come up with the difference in minutes. > In case you're using MySQL, timediff can do the job: http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_timediff Otherwise, just do strtotime(endtime) - strtotime(starttime) / 60. That's the difference in minutes. Regards Peter -- <hype> WWW: http://plphp.dk / http://plind.dk LinkedIn: http://www.linkedin.com/in/plind BeWelcome/Couchsurfing: Fake51 Twitter: http://twitter.com/kafe15 </hype>