Thanks but I still do not get why this does not merit a, "you might want to think about this".
So in the following query: select * from new_payments where closed<>1; it is desired that null=1. DeMorgan's law takes a vacation here. Correct behavior, in that it is a feature, I expected that; desired - no comment. Probably not expected in that selecting for closed=1 and closed<>1 does not yield symmetric results. It was the [not] expected nature that lead me to suggest perhaps an example might be helpful. >From <URL: http://dev.mysql.com/doc/mysql/en/working-with-null.html > Note that in MySQL, 0 or NULL means false and anything else means true. The default truth value from a boolean operation is 1. mysql> select * from new_payments where not closed; Empty set (0.01 sec) So null is not exactly false, just sorta false. I still think this is worth a comment in A.5.3. On Mon, 19 Sep 2005, Roger Baklund wrote: > [EMAIL PROTECTED] wrote: > > I did not expect that null was not not-equal to 1. > > Any comparison with NULL returns NULL: > > mysql> select null<>1,null>1,null<1,null=1; > +---------+--------+--------+--------+ > | null<>1 | null>1 | null<1 | null=1 | > +---------+--------+--------+--------+ > | NULL | NULL | NULL | NULL | > +---------+--------+--------+--------+ > 1 row in set (0.00 sec) > > This is the correct and desired behaviour. > > <URL: http://dev.mysql.com/doc/mysql/en/null-values.html > > <URL: http://dev.mysql.com/doc/mysql/en/working-with-null.html > > <URL: http://dev.mysql.com/doc/mysql/en/problems-with-null.html > > > -- > Roger > _____ Douglas Denault http://www.safeport.com [EMAIL PROTECTED] Voice: 301-469-8766 Fax: 301-469-0601 -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
