Я использую PostgreSQL 9.4.Как получить наибольший интервал дат последовательных записей, имеющих один и тот же статус?
Учитывая таблицу с отметкой времени и булева флагом чтения статуса:
CREATE TABLE status (
id serial NOT NULL,
created timestamp with time zone NOT NULL,
read boolean NOT NULL,
CONSTRAINT status_pkey PRIMARY KEY (id),
CONSTRAINT status_unique_created_read UNIQUE(created, read)
);
Я хочу, чтобы получить наибольший интервал последовательных записей, которые разделяют один и тот же статус. Каждое изменение флага read
должно начинаться с другой группы записей.
Конечная цель - получить максимальный интервал created
дат, которые разделяют статус считывания True
.
В качестве примера, давайте заполнить таблицу с этой записи:
INSERT INTO status (created, read) VALUES ('2016-02-23 14:53:39.668225-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-24 09:00:07.384002-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-26 19:33:00.677397-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-26 19:58:07.070881-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:00:47.831193-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:00:50.632217-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:00:50.655375-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:00:54.146508-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:00:56.524389-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:00:58.828541-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:00.809748-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:03.14392-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:05.506604-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:07.606256-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:09.986617-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:12.275312-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:14.194565-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:16.429208-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:18.657266-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:20.877406-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-28 09:01:23.122152-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-29 10:37:25.036703-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-29 11:07:10.564814-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-29 11:47:38.78204-03', false);
INSERT INTO status (created, read) VALUES ('2016-02-29 11:56:49.895785-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-29 12:46:07.906734-03', false);
INSERT INTO status (created, read) VALUES ('2016-02-29 17:19:09.776746-03', true);
INSERT INTO status (created, read) VALUES ('2016-02-29 17:24:07.145661-03', false);
INSERT INTO status (created, read) VALUES ('2016-02-29 21:11:02.558749-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-01 09:00:00.871397-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-01 10:46:17.66168-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-01 14:12:43.717506-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-02 09:00:04.303278-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-02 17:33:16.196374-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-02 17:36:29.84208-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-03 09:00:01.929879-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-03 09:00:01.940345-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-04 09:00:03.120712-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-04 10:59:01.651798-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-04 17:06:27.565846-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-04 17:07:00.258593-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-04 17:30:23.126116-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-04 17:43:41.512822-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-05 09:00:13.42016-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-06 09:00:05.610203-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-07 16:33:58.102805-03', false);
INSERT INTO status (created, read) VALUES ('2016-03-07 16:53:48.820488-03', false);
INSERT INTO status (created, read) VALUES ('2016-03-07 18:51:44.182288-03', false);
INSERT INTO status (created, read) VALUES ('2016-03-09 09:00:04.369842-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-09 09:00:04.380432-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-09 09:00:04.450373-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-09 09:00:04.598239-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-09 09:00:04.7075-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-10 09:00:00.923048-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-11 09:00:01.02605-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-11 16:34:43.341189-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-11 18:39:02.517519-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-11 18:39:02.535953-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-15 09:00:01.405166-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-15 12:08:51.729326-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-16 09:00:01.594785-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-17 09:00:01.189489-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-18 09:00:01.105867-03', true);
INSERT INTO status (created, read) VALUES ('2016-03-18 15:32:03.153641-03', false);
INSERT INTO status (created, read) VALUES ('2016-03-21 10:21:18.110903-03', false);
INSERT INTO status (created, read) VALUES ('2016-03-22 10:34:29.630107-03', false);
Сгруппированные данные могут выглядеть следующим образом:
min_created;max_created;read;count
"2016-02-23 14:53:39.668225-03";"2016-02-29 11:07:10.564814-03";TRUE;23
"2016-02-29 11:47:38.78204-03";"2016-02-29 11:47:38.78204-03";FALSE;1
"2016-02-29 11:56:49.895785-03";"2016-02-29 11:56:49.895785-03";TRUE;1
"2016-02-29 12:46:07.906734-03";"2016-02-29 12:46:07.906734-03";FALSE;1
"2016-02-29 17:19:09.776746-03";"2016-02-29 17:19:09.776746-03";TRUE;1
"2016-02-29 17:24:07.145661-03";"2016-02-29 17:24:07.145661-03";FALSE;1
"2016-02-29 21:11:02.558749-03";"2016-03-06 09:00:05.610203-03";TRUE;17
"2016-03-07 16:33:58.102805-03";"2016-03-07 18:51:44.182288-03";FALSE;3
"2016-03-09 09:00:04.369842-03";"2016-03-18 09:00:01.105867-03";TRUE;15
"2016-03-18 15:32:03.153641-03";"2016-03-22 10:34:29.630107-03";FALSE;3
И ответ на what's the greatest interval of dates between read status
должно быть:
"2016-03-09 09:00:04.369842-03";"2016-03-18 09:00:01.105867-03"
Как получить этот результат с помощью SQL?
Спасибо! Я проверю ваш ответ. –
Это сработало! Благодаря! –