doubledee Posted March 18, 2012 Share Posted March 18, 2012 If I want to subtract a Date/Time in Record #1 from Record #2, how would I do that? Debbie Link to comment https://forums.phpfreaks.com/topic/259183-comparing-records/ Share on other sites More sharing options...
Pikachu2000 Posted March 18, 2012 Share Posted March 18, 2012 TIMEDIFF() Link to comment https://forums.phpfreaks.com/topic/259183-comparing-records/#findComment-1328649 Share on other sites More sharing options...
doubledee Posted March 18, 2012 Author Share Posted March 18, 2012 TIMEDIFF() That isn't what I asked about... I asked how to do math on RECORDS (as opposed to VALUES). Even more so, if I had 100 records, and I wanted to subtract adjacent Records, then how would I do that? Record 1 - Record 2 Record 2 - Record 3 Record 3 - Record 4 : : : Debbie Link to comment https://forums.phpfreaks.com/topic/259183-comparing-records/#findComment-1328652 Share on other sites More sharing options...
fenway Posted March 18, 2012 Share Posted March 18, 2012 SQL isn't designed to operate on pairs of rows -- you'll have to fake it with a user variable, or use a self-join, assuming you "know" how to find record N+1. Link to comment https://forums.phpfreaks.com/topic/259183-comparing-records/#findComment-1328787 Share on other sites More sharing options...
doubledee Posted March 18, 2012 Author Share Posted March 18, 2012 SQL isn't designed to operate on pairs of rows -- you'll have to fake it with a user variable, or use a self-join, assuming you "know" how to find record N+1. So INSERTING a new record everytime a User hopes from Page to Page and then trying to subtract the TimeStamps of each record to determine the "Time on page" wouldn't be a good strategy, huh? Debbie Link to comment https://forums.phpfreaks.com/topic/259183-comparing-records/#findComment-1328827 Share on other sites More sharing options...
fenway Posted March 25, 2012 Share Posted March 25, 2012 Oh, it can be done -- it just might be easier to calculate in PHP if this is a "one-time" thing, and then update the corresponding rows. Link to comment https://forums.phpfreaks.com/topic/259183-comparing-records/#findComment-1330902 Share on other sites More sharing options...
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