From: | dave <audiotecture(at)web(dot)de> |
---|---|
To: | pgsql-sql(at)postgresql(dot)org |
Subject: | Recursive merging of overlapping arrays in a column |
Date: | 2015-09-20 11:12:36 |
Message-ID: | 1442747556700-5866560.post@n5.nabble.com |
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Thread: | |
Lists: | pgsql-sql |
Hey mailing list,
i have the following Table:
I want to merge the arrays which have overlapping elements, so that I get
the result which doesn't contain overlapping arrays anymore:
I am not an expert in SQL and it took me a long time to come up with this
solution:
Which gives me the result:
Result number 3 is contained in number one and shouldn't be in the output
anymore, because I only want non overlapping arrays in the result.
Another problem I encountered is that the performance of this query seems to
be very bad. I tried running it on a larger table (~400000 arrays) and it is
still running after ~10h.
I would appreciate any input on this problems, so it would be nice if anyone
could give me a hint how to get only the merged arrays without overlaps in
the resultset and maybe how to build a more elegant and efficient query.
Thanks in advance,
Dave
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