From: Leon Stringer <leon.stringer@ntlworld.com>
To: pgsql-sql@postgresql.org
Subject: Consecutive row count query
Date: Thu, 17 Mar 2005 20:21:24 +0000
Message-ID: <1111090884.22783.5.camel@localhost.localdomain> (raw)
Hi,
I wondered if anyone could answer the following question:
If I have a table such as the one below:
col1 col_order
-----------
Apple 1
Apple 2
Orange 3
Banana 4
Apple 5
Is there a way I can get the following results:
Apple 2
Orange 1
Banana 1
Apple 1
i.e. Each row is printed ordered by col_order but consecutive
appearances of the same col1 result in only a single line in the result
with the number of consecutive appearances.
Obviously I could store the table as:
col1 col_order col_count
--------------------------
Apple 1 2
Orange 2 1
Banana 3 1
Apple 4 1
But since (in my intended table) most rows will have col_count = 1, this
seems like unnecessary normalization (and semantically "wrong").
Thanks in advance for any help,
Leon Stringer
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Subject: Re: Consecutive row count query
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