From: | Leon Stringer <leon(dot)stringer(at)ntlworld(dot)com> |
---|---|
To: | pgsql-sql(at)postgresql(dot)org |
Subject: | Consecutive row count query |
Date: | 2005-03-17 20:21:24 |
Message-ID: | 1111090884.22783.5.camel@localhost.localdomain |
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Thread: | |
Lists: | pgsql-sql |
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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