With source data... On 19 October 2012 16:40, Liam Caffrey <liam.caff...@gmail.com> wrote:
> Hi, > > I am trying to run a recursive cte query on temporal data. > I attach the starting set (temp_station) and the solution set > (temp_solution) > > A user visits many stations in random order. > They can enter a station many times but they only exit once. > After they enter a station X, they can enter other stations or exit other > stations, i.e. a station entry/exit can fully contain other stations) but > eventually they will exit station X (these are invalid visits to other > stations within an entry/exit context for a single station.) > They can validly visit a station multiple times but these visits must not > overlap with each other. > > The objective is to list the earliest entry time and matching exit time > for each valid visit to a station according to the rules above. > > My attempt below doesn't recurse and I can't understand what I need to do > here. Can anyone shed some light on this? > > Regards > > Liam > > --drop table temp_station; > > create table temp_station > ( > station_id int > ,movement_direction varchar(5) > ,event_tick char(3) > ,event_time timestamp with time zone > ); > > delete from temp_station; > > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (1, 'enter', 't01', '2012-10-18 10:23:31'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (1, 'enter', 't02', '2012-10-18 10:31:42'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (1, 'enter', 't03', '2012-10-18 10:41:41'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (1, 'exit', 't04', '2012-10-18 10:48:34'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (2, 'enter', 't05', '2012-10-18 10:54:57'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (2, 'exit', 't06', '2012-10-18 11:01:35'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (3, 'enter', 't07', '2012-10-18 11:10:52'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (3, 'enter', 't08', '2012-10-18 11:20:50'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (4, 'enter', 't09', '2012-10-18 11:29:56'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (3, 'enter', 't10', '2012-10-18 11:37:53'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (7, 'exit', 't11', '2012-10-18 11:44:42'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (3, 'exit', 't12', '2012-10-18 11:53:14'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (4, 'enter', 't13', '2012-10-18 12:02:59'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (4, 'enter', 't14', '2012-10-18 12:12:11'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (4, 'exit', 't15', '2012-10-18 12:20:29'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (2, 'enter', 't16', '2012-10-18 12:26:57'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (2, 'enter', 't17', '2012-10-18 12:34:12'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (9, 'exit', 't18', '2012-10-18 12:40:10'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (2, 'exit', 't19', '2012-10-18 12:48:29'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (5, 'enter', 't20', '2012-10-18 12:54:37'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (5, 'exit', 't21', '2012-10-18 13:00:42'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (6, 'enter', 't22', '2012-10-18 13:06:09'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (6, 'enter', 't23', '2012-10-18 13:15:47'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (6, 'exit', 't24', '2012-10-18 13:23:34'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (6, 'enter', 't25', '2012-10-18 13:29:22'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (6, 'enter', 't26', '2012-10-18 13:37:27'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (5, 'exit', 't27', '2012-10-18 13:45:02'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (6, 'exit', 't28', '2012-10-18 13:53:44'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (7, 'enter', 't29', '2012-10-18 14:00:09'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (7, 'enter', 't30', '2012-10-18 14:08:45'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (8, 'enter', 't31', '2012-10-18 14:14:12'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (8, 'exit', 't32', '2012-10-18 14:20:20'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (7, 'exit', 't33', '2012-10-18 14:28:23'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (2, 'enter', 't34', '2012-10-18 14:35:43'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (2, 'exit', 't35', '2012-10-18 14:44:34'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (8, 'enter', 't36', '2012-10-18 14:51:26'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (8, 'enter', 't37', '2012-10-18 14:59:08'); > insert into temp_station (station_id, movement_direction, event_tick, > event_time) values (8, 'exit', 't38', '2012-10-18 15:06:10'); > > > --drop table temp_solution; > > create table temp_solution > ( > station_id int > ,movement_direction varchar(5) > ,event_tick char(3) > ,event_time timestamp with time zone > ); > > delete from temp_solution; > > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (1, 'enter', 't01', '2012-10-18 10:23:31'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (1, 'exit', 't04', '2012-10-18 10:48:34'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (2, 'enter', 't05', '2012-10-18 10:54:57'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (2, 'exit', 't06', '2012-10-18 11:01:35'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (3, 'enter', 't07', '2012-10-18 11:10:52'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (3, 'exit', 't12', '2012-10-18 11:53:14'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (4, 'enter', 't13', '2012-10-18 12:02:59'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (4, 'exit', 't15', '2012-10-18 12:20:29'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (2, 'enter', 't16', '2012-10-18 12:26:57'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (2, 'exit', 't19', '2012-10-18 12:48:29'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (5, 'enter', 't20', '2012-10-18 12:54:37'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (5, 'exit', 't21', '2012-10-18 13:00:42'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (6, 'enter', 't22', '2012-10-18 13:06:09'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (6, 'exit', 't24', '2012-10-18 13:23:34'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (6, 'enter', 't25', '2012-10-18 13:29:22'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (6, 'exit', 't28', '2012-10-18 13:53:44'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (7, 'enter', 't29', '2012-10-18 14:00:09'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (7, 'exit', 't33', '2012-10-18 14:28:23'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (2, 'enter', 't34', '2012-10-18 14:35:43'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (2, 'exit', 't35', '2012-10-18 14:44:34'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (8, 'enter', 't36', '2012-10-18 14:51:26'); > insert into temp_solution (station_id, movement_direction, event_tick, > event_time) values (8, 'exit', 't38', '2012-10-18 15:06:10'); > > > with recursive > enter_event as > ( > select row_number() over(order by event_time) as rownum, * > from temp_station > where movement_direction = 'enter' > --and station_id in (7, 8) > ) > ,exit_event as > ( > select row_number() over(order by event_time) as rownum, * > from temp_station > where movement_direction = 'exit' > --and station_id in (7, 8) > ) > ,event_period as > ( > select a.rownum, a.station_id, a.event_tick as start_tick, b.event_tick as > end_tick, a.event_time as start_time, b.event_time as end_time > from enter_event a > join > exit_event b > on a.station_id = b.station_id > -- entry always before exit > and a.event_time < b.event_time > ) > ,dtr (rownum, station_id, start_tick, end_tick, start_time, end_time) as > ( > select rownum, station_id, start_tick, end_tick, start_time, end_time > from event_period > where start_tick = (select min(start_tick) from event_period) > union all > select a.rownum, a.station_id, a.start_tick, a.end_tick, a.start_time, > b.end_time > from event_period a > ,dtr b > where a.end_time < b.start_time > and a.start_time < a.end_time > and b.start_time < b.end_time > ) > select * from dtr > > > > > >