multi recordset and data type check was: Re: PL/pgSQL stored procedure returning multiple result sets (SELECTs)?

On Mon, 13 Oct 2008 12:17:21 +0300
Vladimir Dzhuvinov  wrote:

> CREATE PROCEDURE list_user_accounts(IN user_id INT)
> 
> 	BEGIN
> 
> 	-- Return first result set (single row)
> 	SELECT * FROM users WHERE id = user_id;
> 
> 	-- Return second result set (zero or more rows)
> 	SELECT * FROM accounts WHERE account_holder = user_id;
> 
> 	END;

I'd say returning multiple recordset is useful to save connections
and transferred data.
You can't get the same with a left join (users fields will be
repeated over and over) and you can't get the same with 2 separated
statements since they will need 2 connections.

But from the client side, suppose it PHP... if the first
statement return no record and the second one return 3 records, how
can I know?
What about functions like pg_num_fields?

-- 
Ivan Sergio Borgonovo
http://www.webthatworks.it