Re: WHERE != and NULLS

Jonathan Leffler wrote: > > Doesn't NULL mean the absence of value. That is different from > >unknown. > > It depends on who you speak to. CJ Date has no patience with nulls in any > shape or form. EF Codd wants at least two different versions of 'marks', [SNIP] Lets take a simpler look at NULL. Define NULL to be the empty set. Relational theory states that A X NULL = NULL [I dont have a character for the empty set. [STUFF ABOUT RELIGION] Mathematically speaking, anything compared to NULL is NULL, so that Informix is correct in giving an *erroneous* value back. A + B + NULL is = NULL. Its sort of like asking how many pixies can dance on the head of a pin. The answer depends on the type of music. Clasical Waltz or Slam dancing? [Besides I realize the original quote uses angels. That one is easy. Everyone knows angels can't dance ;-] -Mikey