Обсуждение: Merge overlapping time-periods

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Merge overlapping time-periods

От

"Jira, Marcel"

Дата:

15 июня 2011 г., 12:29:13

Hi!

Although I try for some time, I am not able to write an SQL-Query that can do the following:

I have a very big table (let’s call it “mytable”) with information like this:

ID BEG END

1 2000-01-01 2000-03-31

1 2000-04-01 2000-05-31

1 2000-04-15 2000-07-31

1 2000-09-01 2000-10-31

2 2000-02-01 2000-03-15

2 2000-01-15 2000-03-31

2 2000-04-01 2000-04-15

3 2000-06-01 2000-06-15

3 2000-07-01 2000-07-15

There’s an ID and time periods defined by a start value (BEG) and an end value (END)

I want to merge all periods belonging to the same ID, iff their time periods are overlapping or in a direct sequence.

Therefore the result should somehow look like this:

ID  BEG          END

1   2000-01-01   2000-07-31

1   2000-09-01   2000-10-31

2   2000-01-15   2000-03-31

2   2000-04-01   2000-04-15

3   2000-06-01   2000-06-15

3   2000-07-01   2000-07-15

I tried using “WITH RECURSIVE” but I didn’t succeed.

My server is PostgreSQL 8.4. Unfortunately I can’t do anything like update or install some fancy module…

Thank you for your help!

Best regards,

Marcel Jira

Re: Merge overlapping time-periods

От

"F. BROUARD / SQLpro"

Дата:

15 июня 2011 г., 12:44:06

I write a paper on this topic comparing queries for PG, SQL Server and 
MySQL.

Can you read french ?
http://blog.developpez.com/sqlpro/p9821/langage-sql-norme/agregation-d-intervalles-en-sql-1/

The worst query is the RECURSIVE one !

A +


Le 15/06/2011 17:23, Jira, Marcel a écrit :
> Hi!
>
> Although I try for some time, I am not able to write an SQL-Query that
> can do the following:
>
> I have a very big table (let’s call it “mytable”) with information like
> this:
>
> ID  BEG          END
>
> 1   2000-01-01   2000-03-31
>
> 1   2000-04-01   2000-05-31
>
> 1   2000-04-15   2000-07-31
>
> 1   2000-09-01   2000-10-31
>
> 2   2000-02-01   2000-03-15
>
> 2   2000-01-15   2000-03-31
>
> 2   2000-04-01   2000-04-15
>
> 3   2000-06-01   2000-06-15
>
> 3   2000-07-01   2000-07-15
>
> There’s an ID and time periods defined by a start value (BEG) and an end
> value (END)
>
> I want to merge all periods belonging to the same ID, iff their time
> periods are overlapping or in a direct sequence.
>
> Therefore the result should somehow look like this:
>
> ID  BEG          END
>
> 1   2000-01-01   2000-07-31
>
> 1   2000-09-01   2000-10-31
>
> 2   2000-01-15   2000-03-31
>
> 2   2000-04-01   2000-04-15
>
> 3   2000-06-01   2000-06-15
>
> 3   2000-07-01   2000-07-15
>
> I tried using “WITH RECURSIVE” but I didn’t succeed.
>
> My server is PostgreSQL 8.4. Unfortunately I can’t do anything like
> update or install some fancy module…
>
> Thank you for your help!
>
> Best regards,
>
> Marcel Jira
>


-- 
Frédéric BROUARD - expert SGBDR et SQL - MVP SQL Server - 06 11 86 40 66
Le site sur le langage SQL et les SGBDR  :  http://sqlpro.developpez.com
Enseignant Arts & Métiers PACA, ISEN Toulon et CESI/EXIA Aix en Provence
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*********************** http://www.sqlspot.com *************************

Re: Merge overlapping time-periods

От

"Oliveiros d'Azevedo Cristina"

Дата:

15 июня 2011 г., 13:38:01

Howdy, Marcel,

In the example output you provided the ID = 2 should have just one record...Ain't I right?

Best,

Oliveiros

----- Original Message -----
From: Jira, Marcel
To: 'pgsql-sql@postgresql.org'
Sent: Wednesday, June 15, 2011 4:23 PM
Subject: [SQL] Merge overlapping time-periods
Hi!

Although I try for some time, I am not able to write an SQL-Query that can do the following:

I have a very big table (lets call it mytable) with information like this:

ID BEG          END
1   2000-01-01   2000-03-31
1   2000-04-01   2000-05-31
1   2000-04-15   2000-07-31
1   2000-09-01   2000-10-31
2   2000-02-01   2000-03-15
2   2000-01-15   2000-03-31
2   2000-04-01   2000-04-15
3   2000-06-01   2000-06-15
3   2000-07-01   2000-07-15

Theres an ID and time periods defined by a start value (BEG) and an end value (END)

I want to merge all periods belonging to the same ID, iff their time periods are overlapping or in a direct sequence.

Therefore the result should somehow look like this:
ID  BEG          END
1   2000-01-01   2000-07-31
1   2000-09-01   2000-10-31
2   2000-01-15   2000-03-31
2   2000-04-01   2000-04-15
3   2000-06-01   2000-06-15
3   2000-07-01   2000-07-15
I tried using WITH RECURSIVE but I didnt succeed.

My server is PostgreSQL 8.4. Unfortunately I cant do anything like update or install some fancy module

Thank you for your help!

Best regards,

Marcel Jira

Re: Merge overlapping time-periods

От

"Oliveiros d'Azevedo Cristina"

Дата:

15 июня 2011 г., 13:50:03

Hello again, Marcel.

I tried this and it seems to work on the example you provided, iif my understanding is correct and you want the ID=2 to have just one record on final output.

That makes sense to me because

2 2000-01-15 2000-03-31

2 2000-04-01 2000-04-15

are in direct sequence (IMHO) as much as

1 2000-01-01 2000-03-31

1 2000-04-01 2000-05-31

are. Isn't my understanding correct?

Best,

Oliveiros

(SELECT x."ID",x."BEG",x."END"
FROM mytable x
LEFT JOIN
(
SELECT a."ID" as xid ,a."BEG" as xbeg,a."END" as xend,b."ID" as yid,b."BEG" as ybeg,b."END" as yend
FROM mytable a
JOIN mytable b
ON a."ID" = b."ID"
AND (( ((a."BEG",a."END") OVERLAPS (b."BEG",b."END"))
OR ((b."BEG" - a."END") = 1))
AND (a."BEG" <> b."BEG")
AND (b."END" <> a."END"))
) y
ON (((yid = x."ID")
AND (ybeg = x."BEG")
AND (yend = x."END"))
OR ((xid = x."ID")
AND (xbeg = x."BEG")
AND (xend = x."END")))

WHERE yid IS NULL)
UNION (
SELECT x."ID",MIN(x."BEG"),MAX(x."END")
FROM mytable x
LEFT JOIN
(
SELECT a."ID" as xid,a."BEG" as xbeg,a."END" as xend,b."ID" as yid,b."BEG" as ybeg,b."END" as yend
FROM mytable a
JOIN mytable b
ON a."ID" = b."ID"
AND (( ((a."BEG",a."END") OVERLAPS (b."BEG",b."END"))
OR ((a."BEG" - b."END") = 1))
AND (a."BEG" <> b."BEG")
AND (b."END" <> a."END"))
) y
ON (((yid = x."ID")
AND (ybeg = x."BEG")
AND (yend = x."END"))
OR ((xid = x."ID")
AND (xbeg = x."BEG")
AND (xend = x."END")))

WHERE yid IS NOT NULL
GROUP BY x."ID"
)

Howdy, Marcel,

In the example output you provided the ID = 2 should have just one record...Ain't I right?

Best,
Oliveiros
----- Original Message -----
From: Jira, Marcel
To: 'pgsql-sql@postgresql.org'
Sent: Wednesday, June 15, 2011 4:23 PM
Subject: [SQL] Merge overlapping time-periods
Hi!

Although I try for some time, I am not able to write an SQL-Query that can do the following:

I have a very big table (lets call it mytable) with information like this:

ID BEG          END
1   2000-01-01   2000-03-31
1   2000-04-01   2000-05-31
1   2000-04-15   2000-07-31
1   2000-09-01   2000-10-31
2   2000-02-01   2000-03-15
2   2000-01-15   2000-03-31
2   2000-04-01   2000-04-15
3   2000-06-01   2000-06-15
3   2000-07-01   2000-07-15

Theres an ID and time periods defined by a start value (BEG) and an end value (END)

I want to merge all periods belonging to the same ID, iff their time periods are overlapping or in a direct sequence.

Therefore the result should somehow look like this:
ID  BEG          END
1   2000-01-01   2000-07-31
1   2000-09-01   2000-10-31
2   2000-01-15   2000-03-31
2   2000-04-01   2000-04-15
3   2000-06-01   2000-06-15
3   2000-07-01   2000-07-15
I tried using WITH RECURSIVE but I didnt succeed.

My server is PostgreSQL 8.4. Unfortunately I cant do anything like update or install some fancy module

Thank you for your help!

Best regards,

Marcel Jira

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Обсуждение: Merge overlapping time-periods

Merge overlapping time-periods

Re: Merge overlapping time-periods

Re: Merge overlapping time-periods

Re: Merge overlapping time-periods