Re: Merging two columns into one

From: "Oliver Elphick" <olly(at)lfix(dot)co(dot)uk>
To: Christopher Sawtell <csawtell(at)xtra(dot)co(dot)nz>
Cc: "Gary MacMinn" <G(dot)MacMinn(at)nca(dot)gov(dot)au>, pgsql-sql(at)postgresql(dot)org
Subject: Re: Merging two columns into one
Date: 2000-06-23 05:53:37
Message-ID: 200006230553.e5N5rde14918@linda.lfix.co.uk
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Christopher Sawtell wrote:
>On Fri, 23 Jun 2000, Gary MacMinn wrote:
>> Hi All,
>>
>> I have two columns in a table (areacode and phone number) that I'd like to
> merge
>into one (phone number) containing both sets of info. Could anyone suggest a
>simple way of achieving this?
>
>export the data to a file using the copy command,
>remove the delimiter with the unix command 'tr -d'
>import the file, now minus the delimeter using the copy command.

Surely tr will remove ALL the delimiters, so this is not helpful
unless these columns are the only ones in the table. You would
have to use awk or perl to process the exported file and delete
the correct delimiter.

For an SQL solution, how about:

SELECT col1, col2,..., areacode || phone as phone, colx, coly,...
INTO new_table
FROM table;

Then you can drop the old table and recreate it with the correct
columns and import the data into it from new_table. (You could
just rename new_table if it doesn't need to be created with
constraints.)

--
Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
Isle of Wight http://www.lfix.co.uk/oliver
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