Thread: Help with SQL Function

I'm falling at the first hurdle.  Can someone tell me how to pass an
attribute value into a function, as I'm trying to do below?  I've studied
the docs every which way, but can't seem to find the cause of my problem.
Thanks in advance for ignorance relief.

extracts=# create function testfunc(text) returns int4 as '
extracts'# select count (*) from dedcolo where equip_type = ''$1''    ---
That's doubled single quotes
extracts'# ' language 'sql';
CREATE
extracts=# select testfunc('Dialup');
 testfunc
----------
        0
(1 row)
extracts=# create function testfunc() returns int4 as '
extracts'# select count (*) from dedcolo where equip_type = ''Dialup''   ---
Doubled single quotes, again
extracts'# ' language 'sql';
CREATE
extracts=# select testfunc();
 testfunc
----------
     3453
(1 row)

Simpler than you think:
select count (*) from dedcolo where equip_type = $1

(note the space between = and $)


On Wed, 3 Jan 2001, Jeff Eckermann wrote:

> I'm falling at the first hurdle.  Can someone tell me how to pass an
> attribute value into a function, as I'm trying to do below?  I've studied
> the docs every which way, but can't seem to find the cause of my problem.
> Thanks in advance for ignorance relief.
>
> extracts=# create function testfunc(text) returns int4 as '
> extracts'# select count (*) from dedcolo where equip_type = ''$1''    ---
> That's doubled single quotes
> extracts'# ' language 'sql';
> CREATE
> extracts=# select testfunc('Dialup');
>  testfunc
> ----------
>         0
> (1 row)
> extracts=# create function testfunc() returns int4 as '
> extracts'# select count (*) from dedcolo where equip_type = ''Dialup''   ---
> Doubled single quotes, again
> extracts'# ' language 'sql';
> CREATE
> extracts=# select testfunc();
>  testfunc
> ----------
>      3453
> (1 row)
>
>

Thanks, Tom, and also to Alex Pilosov for his answer.
I was extrapolating from the plpgsql docs, which I probably didn't
understand correctly.
Programming By Example (which is what we non-programmers are obliged to do)
doesn't work so well when the docs are somewhat sparse.
Are there any plans to expand the docs on plpgsql, since there are new
features coming?  Plpgsql looks like a good tool for enhancing my
development of financial etc reports, but in working with it, I've had two
weeks of frustration and not much of anything else so far.

> -----Original Message-----
> From:    Tom Lane [SMTP:tgl@sss.pgh.pa.us]
> Sent:    Saturday, January 06, 2001 3:41 PM
> To:    Jeff Eckermann
> Cc:    pgsql-general@postgresql.org
> Subject:    Re: [GENERAL] Help with SQL Function
>
> Jeff Eckermann <jeff@akira.eckermann.com> writes:
> > extracts=# create function testfunc(text) returns int4 as '
> > extracts'# select count (*) from dedcolo where equip_type = ''$1''
> --- That's doubled single quotes
> > extracts'# ' language 'sql';
> > CREATE
>
> That's looking for rows where equip_type = '$1'  ... ie, the literal
> string $1.  What you probably wanted is
>
> create function testfunc(text) returns int4 as '
> select count (*) from dedcolo where equip_type = $1
> ' language 'sql';
>
>             regards, tom lane