am Fri, dem 26.01.2007, um 11:39:03 +0200 mailte Suha Onay folgendes:
> Hi,
>
> How can i find the number of days in the intersection of 2 date interval?
> For example:
> 1st interval: (10.01.2007, 20.01.2007)
> 2nd interval: (13.01.2007, 21.01.2007)
> The intersection dates are: 13,14,15,16,17,18,19, 20
> The result is: 8
>
> How can i find the result, 8 in an sql query without using CASE statements?
Some time ago i wrote a function for this, i hope it's helpfull for you:
(not realy tested, be careful!)
create type start_end as (t1 timestamptz, t2 timestamptz);
create or replace function time_intersect (timestamptz, timestamptz, timestamptz, timestamptz) returns start_end as $$
declare _s1 alias for $1; _e1 alias for $2; _s2 alias for $3; _e2 alias for $4;
_start timestamptz; _end timestamptz; _return start_end;
begin
if _s1 < _s2 then _start := _s2; else _start := _s1; end if;
if _e1 < _e2 then _end := _e1; else _end := _e2; end if;
if _start < _end then _return.t1 := _start; _return.t2 := _end; else
_return.t1 := NULL; _return.t2 := NULL; end if;
return _return;
end
$$ language plpgsql;
test=# set datestyle=german;
SET
test=*# select time_intersect('10.01.2007'::date, '20.01.2007'::date, '13.01.2007'::date, '21.01.2007'::date);
time_intersect
-------------------------------------------------------("13.01.2007 00:00:00 CET","20.01.2007 00:00:00 CET")
(1 row)
test=*# select *, t2-t1 from time_intersect('10.01.2007'::date, '20.01.2007'::date, '13.01.2007'::date,
'21.01.2007'::date); t1 | t2 | ?column?
-------------------------+-------------------------+----------13.01.2007 00:00:00 CET | 20.01.2007 00:00:00 CET | @ 7
days
(1 row)
Andreas
--
Andreas Kretschmer
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