Re: Implementation of boolean types.

Jonathan Leffler <jleffler_at_earthlink.net> writes:
> SQL-1999 and SQL-2003 both have a BOOLEAN type, with recognized values
> TRUE, FALSE and UNKNOWN. I'm not clear whether NULL is equivalent to
> UNKNOWN or not; I've not scrutinized the weasel-words carefully enough.

old 3-value logic posting
http://www.garlic.com/~lynn/2003g.html#40 How to cope with missing values - NULLS? http://www.garlic.com/~lynn/2004l.html#75 NULL

reference to Dec. '92, article by CJ Date

-- 
Anne & Lynn Wheeler | http://www.garlic.com/~lynn/