Folks,
I wrote this PL/pgSQL function for my current project, and thought it
would be generally useful. An expansion of the builtin
overlaps(dt1,dt2,dt3,dt4) function, this function returns the interval
of time for which the two datetime ranges overlap.
Roberto, please include this in your online PL/pgSQL function library.
CREATE FUNCTION overlap_interval(DATETIME, DATETIME, DATETIME, DATETIME)
RETURNS INTERVAL AS '
DECLAREbegin1 ALIAS for $1;end1 ALIAS for $2;begin2 ALIAS for $3;end2 ALIAS for $4;overlap_amount INTERVAL;
BEGIN--test for overlap using the ovelap function.--if not found, return 0 interval.
IF NOT overlaps(begin1, end1, begin2, end2) THEN RETURN ''00:00:00''::INTERVAL;END IF;
--otherwise, test for the various forms of overlap
IF begin1 < begin2 THEN IF end1 < end2 THEN overlap_amount := end1 - begin2; ELSE overlap_amount :=
end2- begin2; END IF;ELSE IF end1 < end2 THEN overlap_amount := end1 - begin1; ELSE
overlap_amount:= end2 - begin1; END IF;END IF;
RETURN overlap_amount;
END;'
LANGUAGE 'plpgsql';
-Josh Berkus
______AGLIO DATABASE SOLUTIONS___________________________ Josh Berkus Complete
informationtechnology josh@agliodbs.com and data management solutions (415) 565-7293 for law firms, small
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