At 9:38 -0400 10/27/01, jim barchuk wrote: >Hi Carl! > >> Paul DuBois writes: >> >> > NULL basically means "unknown value", so saying WHERE x = NULL cannot >> > work, even if x is NULL. That means "where one unknown value = another >> > unknown value", which cannot be evaluated with any certainty. :-) >> >> It is sort of odd, though, that x = NULL returns something which >> appears to be undefined rather than something well-defined >> (such as false all the time) or an error (which could be said to >> be well-defined, if errors are considered to be valid responses >> to queries...). > >Well which would you prefer, false or error? Dealing with errors is >annoying if not necessary. 'False' is incorrect -if- the field is allowed >to contain 'nothing' because NULL means it does contain nothing.
I think what Carl meant was that it was strange that the WHERE x = NULL query returned a non-empty result set. I noticed that in the original message, too. I don't know what accounts for it. >jb > >ob-filter-words: database table sql > >-- >jim barchuk >[EMAIL PROTECTED] --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
