How to find earlest possible start times for given duration excluding reservations - Mailing list pgsql-general
From | Andrus |
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Subject | How to find earlest possible start times for given duration excluding reservations |
Date | |
Msg-id | 7A4EEF03D57944E88A87FE1F72E2EDE9@dell2 Whole thread Raw |
Responses |
Re: How to find earlest possible start times for given
duration excluding reservations
|
List | pgsql-general |
Hi! I'm looking for finding ealiest possible start times from reservations table. People work from 10:00AM to 21:00PM in every week day except Sunday and public holidays. Jobs for them are reserved at 15 minute intervals and whole job must fit to single day. Job duration is from 15 minutes to 4 hours. Reservat table contains reservations, yksus2 table contains workes and pyha table contains public holidays. Table structures are below. Reservat structure can changed if this helps. How to first earliest 30 possible start times considering existing reservations ? For example, Mary has already reservation at 12:30 .. 16:00 and John has already reservation at 12:00 to 13:00 In this case query for job with duration of 1.5 hours should return John 2014-10-28 10:00 Mary 2014-10-28 10:00 John 2014-10-28 10:30 Mary 2014-10-28 10:30 Mary 2014-10-28 11:00 John 2014-10-28 13:00 Mary 2014-10-28 16:00 Mary 2014-10-28 16:30 ... etc and also starting from next days I tried query based on answer in http://stackoverflow.com/questions/13433863/how-to-return-only-work-time-from-reservations-in-postgresql below but it returns wrong result: MARY 2014-10-28 13:00:00 MARY 2014-10-29 22:34:40.850255 JOHN 2014-10-30 22:34:40.850255 MARY 2014-10-31 22:34:40.850255 MARY 2014-11-03 22:34:40.850255 Also sliding start times 10:00, 10:30 etc are not returned. How to get proper first reservations ? Query which I tried is insert into reservat (objekt2, during) values ('MARY', '[2014-10-28 11:30:00,2014-10-28 13:00:00)'), ('JOHN', '[2014-10-28 10:00:00,2014-10-28 11:30:00)'); with gaps as ( select yksus, upper(during) as start, lead(lower(during),1,upper(during)) over (ORDER BY during) - upper(during) as gap from ( select yksus2.yksus, during from reservat join yksus2 on reservat.objekt2=yksus2.yksus where upper(during)>= current_date union all select yksus2.yksus, unnest(case when pyha is not null then array[tsrange1(d, d + interval '1 day')] when date_part('dow', d) in (0, 6) then array[tsrange1(d, d + interval '1 day')] when d::date = current_Date then array[ tsrange1(d, current_timestamp ), tsrange1(d + interval '20 hours', d + interval '1 day')] else array[tsrange1(d, d + interval '8 hours'), tsrange1(d + interval '20 hours', d + interval '1 day')] end) from yksus2, generate_series( current_timestamp, current_timestamp + interval '1 month', interval '1 day' ) as s(d) left join pyha on pyha = d::date ) as x ) select yksus, start from gaps where gap >= interval'1hour 30 minutes' order by start limit 30 Schema: CREATE EXTENSION btree_gist; CREATE TABLE Reservat ( id serial primary key, objekt2 char(10) not null references yksus2 on update cascade deferrable, during tsrange not null check( lower(during)::date = upper(during)::date and lower(during) between current_date and current_date+ interval'1 month' and (lower(during)::time >= '10:00'::time and upper(during)::time < '21:00'::time) AND EXTRACT(MINUTE FROM lower(during)) IN (0, 15, 30,45) AND EXTRACT(MINUTE FROM upper(during)) IN (0, 15, 30, 45) and (date_part('dow', lower(during)) in (1,2,3,4,5,6) and date_part('dow', upper(during)) in (1,2,3,4,5,6)) ), EXCLUDE USING gist (objekt2 WITH =, during WITH &&) ); create or replace function holiday_check() returns trigger language plpgsql stable as $$ begin if exists (select * from pyha where pyha in (lower(NEW.during)::date, upper(NEW.during)::date)) then raise exception 'public holiday %', lower(NEW.during) ; else return NEW; end if; end; $$; create trigger holiday_check_i before insert or update on Reservat for each row execute procedure holiday_check(); CREATE OR REPLACE FUNCTION public.tsrange1(start timestamp with time zone, finish timestamp with time zone ) RETURNS tsrange AS $BODY$ SELECT tsrange(start::timestamp without time zone, finish::timestamp without time zone ); $BODY$ language sql immutable; -- Workers create table yksus2( yksus char(10) primary key); insert into yksus2 values ('JOHN'), ('MARY'); -- public holidays create table pyha( pyha date primary key); I posted it also in http://stackoverflow.com/questions/26608683/how-to-find-first-free-start-times-from-reservations-in-postgres Andrus.
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