From: Adrian Klaver <adrian.klaver@gmail.com>
To: James Sharrett <jsharrett@tidemark.net>
Cc: pgsql-sql@postgresql.org
Subject: Re: returning the number of rows output by a copy command from a function
Date: Wed, 16 Jan 2013 08:42:43 -0800
Message-ID: <50F6D883.50901@gmail.com> (raw)
In-Reply-To: <CD1C3FE5.6D0E%jsharrett@tidemark.net>
References: <CD1C3FE5.6D0E%jsharrett@tidemark.net>
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On 01/16/2013 08:30 AM, James Sharrett wrote:
> I have a function that generates a table of records and then a SQL
> statement that does a COPY into a text file. I want to return the
> number of records output into the text file from my function. The
> number of rows in the table is not necessarily the number of rows in the
> file due to summarization of data in the table on the way out. Here is
> a very shortened version of what I'm doing:
>
>
> CREATE OR REPLACE FUNCTION export_data(list of parameters)
> RETURNS integer AS
> $BODY$
>
> declare
> My variables
>
> Begin
>
> { A lot of SQL to build and populate the table of records to export}
>
>
> strSQL := 'copy (select MyColumns from MyExportTable) to MyFile.csv with
> CSV HEADER;';
> Execute strSQL;
>
> Return 0;
>
> end
> $BODY$
> LANGUAGE plpgsql VOLATILE
>
> strSQL gets dynamically generated so it's not a static statement.
>
> This all works exactly as I want. But when I try to get the row count
> back out I cannot get it. I've tried the following:
>
> 1.
> strSQL := 'copy (select MyColumns from MyExportTable) to MyFile.csv with
> CSV HEADER;';
> Execute strSQL into export_count;
>
> Return export_count;
>
> This give me an error saying that I've tried to use the INTO statement
> with a command that doesn't return data.
>
>
> 2.
> strSQL := 'copy (select MyColumns from MyExportTable) to MyFile.csv with
> CSV HEADER;';
> Execute strSQL;
>
> Get diagnostics export_count = row_count;
>
> This always returns zero.
>
> 3.
> strSQL := 'copy (select MyColumns from MyExportTable) to MyFile.csv with
> CSV HEADER;';
> Execute strSQL;
>
> Return row_count;
>
> This returns a null.
>
> Any way to do this?
If it helps:
http://www.postgresql.org/docs/9.2/interactive/sql-copy.html
"
On successful completion, a COPY command returns a command tag of the form
COPY count
The count is the number of rows copied.
"
So it looks like you will need to parse the string for the count.
>
>
> Thanks in advance,
> James
>
--
Adrian Klaver
adrian.klaver@gmail.com
--
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To: pgsql-sql@postgresql.org
Cc: adrian.klaver@gmail.com, jsharrett@tidemark.net
Subject: Re: returning the number of rows output by a copy command from a function
In-Reply-To: <50F6D883.50901@gmail.com>
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