From: Jim Nasby <decibel@decibel.org>
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Subject: Inconsistency in docs for OVERLAPS
Date: Tue, 20 Apr 2010 18:34:00 -0500
Message-Id: <1FF2D1B3-E932-44FA-93F5-EFDD843C5781@decibel.org>
To: PostgreSQL-documentation <pgsql-docs@postgresql.org>
Mime-Version: 1.0 (Apple Message framework v1078)

Per 8.3 and 8.4 docs:

"In addition to these functions, the SQL OVERLAPS operator is supported:

(start1, end1) OVERLAPS (start2, end2)
(start1, length1) OVERLAPS (start2, length2)
This expression yields true when two time periods (defined by their =
endpoints) overlap, false when they do not overlap. The endpoints can be =
specified as pairs of dates, times, or time stamps; or as a date, time, =
or time stamp followed by an interval."

So we accept (datetime,datetime) OVERLAPS (datetime,datetime) or =
(datetime,interval) OVERLAPS (datetime,interval)

However, the example shows yet another case:

"SELECT (DATE '2001-02-16', DATE '2001-12-21') OVERLAPS

       (DATE '2001-10-30', DATE '2002-10-30');

Result: true

SELECT (DATE '2001-02-16', INTERVAL '100 days')=20
OVERLAPS

       (DATE '2001-10-30', DATE '2002-10-30');

Result: false

And in reality, (timestamp, interval) OVERLAPS (timestamp, timestamp) =
does work, first part of this is incomplete.
--
Jim C. Nasby, Database Architect                   jim@nasby.net
512.569.9461 (cell)                         http://jim.nasby.net