On 20 Dec 2013, at 4:11am, David Bicking <dbic...@yahoo.com> wrote: > But isn't NULL and 0 a NULL? So wouldn't it need to evaluate X to determine > if it was null, and thus discover it wasn't a valid column name and return an > error?
In SQL, where anything can be NULL, binary operation tables must be written out with three rows and columns: true, false, and NULL. And if you do that, you find that both "0 AND NULL" and "NULL AND 0" evaluate to 0. I must put "You can't just see a NULL somewhere in an expression and jump to the conclusion that the answer is NULL." somewhere. It's pretty neat. Thanks for the reminder. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
