Re: Unique Keys
From: --CELKO-- <jcelko212_at_earthlink.net>
Date: 27 Nov 2004 15:55:25 -0800
Message-ID: <18c7b3c2.0411271555.2d0a2237_at_posting.google.com>
Date: 27 Nov 2004 15:55:25 -0800
Message-ID: <18c7b3c2.0411271555.2d0a2237_at_posting.google.com>
The syntax for that predicate in SQL-92 is:
(S1, T1) OVERLAPS (S2, T2)
and it is defined as:
(S1 > S2 AND NOT (S1 >= T2 AND T1 >= T2))
OR (S2 > S1 AND NOT (S2 >= T1 AND T2 >= T1))
OR (S1 = S2 AND (T1 <> T2 OR T1 = T2))
Rick Snodgrass introduced this into the standards. Received on Sun Nov 28 2004 - 00:55:25 CET