Just to be absolutely clear, NULL /= 0 (zero). This goes beyond mysql. On some IBM mainframes NULL is actually a distinct representation from zero. On most pc's

Just to be absolutely clear, NULL /= 0 (zero). This goes beyond mysql. On some IBM mainframes NULL is actually a distinct representation from zero. On most pc's, null is overloaded with 0. Pr1me for example used 017777600000 as null. Data General MV encoded the ring level in the top bits of a null value. A similar case s NaN /= 0. Except more people know and understand that rule.