On 06/10/12 11:42, Anton Gavazuk wrote:
Hi dear community,
Have probably quite simple task but cannot find the solution,
Imagine the table A with 2 columns start and end, data type is date
start end
01 dec. 10 dec
11 dec. 13 dec
17 dec. 19 dec
.....
If I have interval, for example, 12 dec-18 dec, how can I determine
that the interval cannot be fully covered by values from table A
because of the gap 14-16 dec? Looking for solution and unfortunately
nothing has come to the mind yet...
Thanks,
Anton
How about something like the following?
Cheers,
Gavin
DROP TABLE IF EXISTS period;
CREATE TABLE period
(
id serial PRIMARY KEY,
start_date date,
end_date date
);
INSERT INTO period (start_date, end_date) VALUES
('2012-12-01', '2012-12-10'),
('2012-12-11', '2012-12-13'),
('2012-12-17', '2012-12-19'),
('2012-12-20', '2012-12-25');
WITH RECURSIVE
slot (start_date, end_date) AS
(
SELECT
p1.start_date,
p1.end_date
FROM
period p1
WHERE
NOT EXISTS
(
SELECT
1
FROM
period p2
WHERE
p1.start_date = p2.end_date + 1
)
UNION ALL
SELECT
s1.start_date,
p3.end_date
FROM
slot s1,
period p3
WHERE
p3.start_date = s1.end_date + 1
AND p3.end_date > s1.end_date
)
SELECT
s3.start_date,
MIN(s3.end_date)
FROM
slot s3
WHERE
s3.start_date <= '2012-12-01'
AND s3.end_date >= '2012-12-18'
GROUP BY
s3.start_date
/**/;/**/.
