Thread: Using SETOF in plpgsql function
Hello, I'd like to return a set of integer in an pl/pgsql function. How can I do that ? I've tried things like that, put I've an error when executing : CREATE FUNCTION SP_UPLES() RETURNS setof INTEGER AS ' DECLARE ID INTEGER; BEGIN select a into id from foo; return ID ; END; CREATE FUNCTION SP_UPLES() RETURNS setof INTEGER AS ' DECLARE ID setof INTEGER; BEGIN select a into id from foo; return ID ; END; CREATE FUNCTION SP_UPLES() RETURNS setof INTEGER AS ' BEGIN select a into id from foo; return select a from foo; END; Any help is welcomed. Thanks.
As far as i know, you can only return single values from functions at the moment. Regards Graham -----Original Message----- From: pgsql-sql-owner@hub.org [mailto:pgsql-sql-owner@hub.org]On Behalf Of hlefebvre Sent: 23 August 2000 11:08 To: pgsql-sql@postgresql.org Subject: [SQL] Using SETOF in plpgsql function Hello, I'd like to return a set of integer in an pl/pgsql function. How can I do that ? I've tried things like that, put I've an error when executing : CREATE FUNCTION SP_UPLES() RETURNS setof INTEGER AS ' DECLARE ID INTEGER; BEGIN select a into id from foo; return ID ; END; CREATE FUNCTION SP_UPLES() RETURNS setof INTEGER AS ' DECLARE ID setof INTEGER; BEGIN select a into id from foo; return ID ; END; CREATE FUNCTION SP_UPLES() RETURNS setof INTEGER AS ' BEGIN select a into id from foo; return select a from foo; END; Any help is welcomed. Thanks.
Graham Vickrage wrote: > > As far as i know, you can only return single values from functions at the > moment. > > Regards > > Graham Hum, this is possible a least in SQL functions. But maybe impossible in PL/PGSQL
hlefebvre wrote: > Hello, > > I'd like to return a set of integer in an pl/pgsql function. How can I > do that ? You can't. Not with PL/pgSQL nor with any other PL or C. The problem is nested deeper and requires the planned querytree redesign to get solved. Before you ask: The mentioned redesign will NOT be done for 7.1, and I'm not sure if we will be able to do it for 7.2 yet. Jan -- #======================================================================# # It's easier to get forgiveness for being wrong than for being right. # # Let's break this rule - forgive me. # #================================================== JanWieck@Yahoo.com #
On Wed, 23 Aug 2000, Jan Wieck wrote:
> Before you ask: The mentioned redesign will NOT be done for
> 7.1, and I'm not sure if we will be able to do it for 7.2
> yet.
I hope that 7.2 :-), my query/plan cache is still outside current
interest and if core developers not will work on something like query
path redesign, the query/plan cache will still out.. :-(
Or already test query/plan cache anyone? IMHO it is good merge-able
to current source too.
Karel
PS. sorry of my small sigh for this.... :-)
On Wed, 23 Aug 2000, Jan Wieck wrote:
> You can't. Not with PL/pgSQL nor with any other PL or C. The
> problem is nested deeper and requires the planned querytree
> redesign to get solved.
>
> Before you ask: The mentioned redesign will NOT be done for
> 7.1, and I'm not sure if we will be able to do it for 7.2
> yet.
Just to make sure you've got to know that this is a feature needed
by many users: Add me to the list of users who have a big need for
this!
Kind regards
Andreas.
Jan Wieck <janwieck@Yahoo.com> writes:
> hlefebvre wrote:
>> I'd like to return a set of integer in an pl/pgsql function. How can I
>> do that ?
> You can't. Not with PL/pgSQL nor with any other PL or C. The
> problem is nested deeper and requires the planned querytree
> redesign to get solved.
Not really. Coincidentally enough, I am just in the middle of removing
execQual.c's hard-wired assumption that only SQL-language functions
can return sets. (This is a side effect of fixing the function manager
so that SQL functions can be called in all contexts, eg used as index
functions.) If you want to fix plpgsql so that it retains state and
can produce multiple elements of a set over repeated calls, the same
way that SQL functions do, then it could be done today.
We may well want to rip out that whole approach to set functions later
when we redo querytrees, but the real limitation so far has been bogus
assumptions in the function-call API, not querytrees.
regards, tom lane
Is it possible to copy from a text file that has the fields as fixed width with no delimiter to a table? The other option is a CSV file... but then how do I handle if there is a comma in one of the fields? I'm transfering information from an AS/400 ... if it is into a text file, it is fixed width, if I use Excel, it is Comma separated.
Sort of nevermind, can I can save it tab delimited, but I am still curious if it can be done using fixed width fields. Adam Lang Systems Engineer Rutgers Casualty Insurance Company ----- Original Message ----- From: "Adam Lang" <aalang@rutgersinsurance.com> Cc: <pgsql-sql@postgresql.org> Sent: Wednesday, August 23, 2000 10:38 AM Subject: [SQL] Copy To - fixed width > Is it possible to copy from a text file that has the fields as fixed width > with no delimiter to a table? > > The other option is a CSV file... but then how do I handle if there is a > comma in one of the fields? > > I'm transfering information from an AS/400 ... if it is into a text file, it > is fixed width, if I use Excel, it is Comma separated.
Tom Lane wrote:
> Jan Wieck <janwieck@Yahoo.com> writes:
> > hlefebvre wrote:
> >> I'd like to return a set of integer in an pl/pgsql function. How can I
> >> do that ?
>
> > You can't. Not with PL/pgSQL nor with any other PL or C. The
> > problem is nested deeper and requires the planned querytree
> > redesign to get solved.
>
> Not really. Coincidentally enough, I am just in the middle of removing
> execQual.c's hard-wired assumption that only SQL-language functions
> can return sets. (This is a side effect of fixing the function manager
> so that SQL functions can be called in all contexts, eg used as index
> functions.) If you want to fix plpgsql so that it retains state and
> can produce multiple elements of a set over repeated calls, the same
> way that SQL functions do, then it could be done today.
Not that easy. PL/pgSQL isn't a state machine. The precompiled code is kind of a nested tree of
statements. A RETURN causes a controlled return() through all nested levels of the PL executors C calls. This
mightclose SPI calls in execution as well. Imagine a code construct like
FOR rec IN SELECT * FROM customer LOOP RETURN rec.cust_id AND RESUME; END LOOP;
which would be the correct syntax for returning sets. What happens in PL/pgSQL while execution is, that at the
beginning of the loop the SPI query for SELECT is performed, and then the loop executed for all rows in the SPI
resultset. And of course, you can have nested loops, why not.
Now you want to return the first value. If you really return to the fmgr at this time, the connection to the SPI
manager must be closed, loosing the result set. So how to continue later?
If we want to make it now for sets of scalar values (not tuple sets), we could add another feature to the
fmgrand the PL handlers, which we need later anyway.
In the case of a call to a PL or C function returning a set, the fmgr creates a temp table and calls the
functionwhich fills the temp table with all the return values. Now fmgr changes the execution trees func
nodein a way that it is operating like an SQL function - holding a seqscan over the temp table. After the last
resultis returned, the temp table is removed. This'd work for tuple sets as well (so the temp table then is our
tuple-source).
Jan
--
#======================================================================#
# It's easier to get forgiveness for being wrong than for being right. #
# Let's break this rule - forgive me. #
#================================================== JanWieck@Yahoo.com #