Обсуждение: Function to retrieve the Id column

On Thu, Aug 24, 2006 at 02:07:14PM -0300, Ezequias Rodrigues da Rocha wrote:
> I have Id field that is used in all my database but my more often used
> parameter is a column called "number" that I have in more than 5000 magnetic
> cards, my question is.
> 
> How could I make a function to retrieve this Id just passing the number as
> parameter, just like:
> 
> getCardId(number: varchar)

Are you looking for something like this?

CREATE FUNCTION getCardId(varchar) RETURNS integer AS $$ SELECT id FROM table_name WHERE number = $1;
$$ LANGUAGE sql STABLE STRICT;

Here's an example of how you'd call this function:

SELECT getCardId('123456');

See "Server Programming" in the documentation for more information
about how to write functions.

http://www.postgresql.org/docs/8.1/interactive/server-programming.html
http://www.postgresql.org/docs/8.1/interactive/xfunc-sql.html
http://www.postgresql.org/docs/8.1/interactive/plpgsql.html

-- 
Michael Fuhr