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 (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 END1 2000-01-01 2000-07-311 2000-09-01 2000-10-312 2000-01-15 2000-03-312 2000-04-01 2000-04-153 2000-06-01 2000-06-153 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
