Wie kann das größte Datumsintervall von aufeinander folgenden Datensätzen mit demselben Status abgerufen werden?

Ich benutze PostgreSQL 9.4.Wie kann das größte Datumsintervall von aufeinander folgenden Datensätzen mit demselben Status abgerufen werden?

eine Tabelle mit einem Zeitstempel und einer boolean Flagge von Lesestatus Gegeben:

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) 
);

ich den größten Abstand von aufeinanderfolgenden Datensätze abrufen möchten, die den gleichen Status teilen. Jede Änderung des Flags read sollte eine weitere Gruppe von Datensätzen starten.

Das endgültige Ziel ist es, das größte Intervall von created Daten zu erhalten, die den Lesestatus True teilen.

Als Beispiel nehmen wir die Tabelle mit dieser Aufzeichnungen füllen:

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);

Die gruppierten Daten könnte wie folgt aussehen:

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

Und die Antwort auf die what's the greatest interval of dates between read status sein sollte:

"2016-03-09 09:00:04.369842-03";"2016-03-18 09:00:01.105867-03"

Wie bekomme ich dieses Ergebnis mit SQL?

Quelle

2016-03-22 Fernando Macedo

Die folgende Abfrage generiert alle Gruppen von Intervallen für jeden Status.

select 
    nn.created, 
    (
     select 
      (
       select 
        nn2.created 
       from 
        status nn2 
       where 
        nn2.created < nn1.created 
       and 
        nn2.read = nn.read 
       order by 
        1 desc 
       limit 1 
      ) 
     from 
      status nn1 
     where 
      nn1.created > nn.created 
     and 
      nn1.read <> nn.read 
     order by 
      1 
     limit 1 
    ) as modified, 
    nn.read 
from 
    status nn 
order by 
    nn.created

Sie können es als ein CTE (oder eine Ansicht) zusammen mit einigen SQL Grundfunktionen, die Daten zu der Gruppe aggregieren Sie wollen.

Eg .:

select 
    max(date_part('[year,month,day]',created) - date_part('[year,month,day]',modified)) 
from 
    [cte or view]

Quelle

2016-03-22 17:34:37

Dank! Ich werde deine Antwort testen. –

Es hat funktioniert! Vielen Dank! –

hier eine andere Lösung (funktioniert auch auf anderen db-Motoren)

SELECT min(created), Max(created), read, Count(1) 
FROM ( 
SELECT created, read 
, (SELECT Max(created) FROM status WHERE created < t.created AND read <> t.read) x1 
, (SELECT Min(created) FROM status WHERE created > t.created AND read <> t.read) x2 
FROM status t) 
GROUP BY read, x1, x2 
ORDER BY 1

Quelle

2016-03-22 20:42:47

Schön! Es ist sogar schneller als die erste Antwort. Vielen Dank! –

Wenn Sie die Geschwindigkeit Ihrer Abfrage verbessern müssen, können Sie der Tabelle einen Index hinzufügen (erstellt, gelesen) –

Danke! Ich habe die Frage aktualisiert, um ein ID-Feld und die Indizes aufzunehmen. Ich habe bemerkt, dass Sie die 'min (created)' und 'max (created)' 'in den Unterabfragen verwendet haben, um die Gruppe zu identifizieren. Ersetzen durch 'min (id)' und 'max (id)' funktioniert auch. –

Wie kann das größte Datumsintervall von aufeinander folgenden Datensätzen mit demselben Status abgerufen werden?

Antwort

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