Обсуждение: Executing dynamic queries (EXECUTE)

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Executing dynamic queries (EXECUTE)

От
"Carla Mello"
Дата:
Hello!
 
I need to execute a dynamic query and capture your result in a integer variable.
 
I´m using the statement "EXECUTE string", but I don´t obtain to capture the result of dynamic query.
 
See the example:
 
======================================================
create or replace function f_population_check() returns bigint as
'
declare
   v_tot bigint;
   v_query varchar(4000);
   v_count integer;
   r record;
begin
   v_tot:= 0;
   for r in select * from pg_tables loop
      v_count:= 0;
      v_query := ''select count(*) from '' || r.tablename;
      v_count:= EXECUTE v_query;
      if v_count = 0 then
         RAISE NOTICE ''Empty table % '',r.tablename;
      end if;
      v_tot:= v_tot + 1;
   end loop;
   return v_tot;
end;
'
language 'plpgsql';
======================================================
ERROR:  parse error at or near "$1" at character 18
CONTEXT:  PL/pgSQL function "f_population_check" line 11 at assignment
======================================================
Somebody could help me?
Thanks, Carla Mello.

Re: Executing dynamic queries (EXECUTE)

От
Tomasz Myrta
Дата:
Dnia 2004-01-27 16:25, Użytkownik Carla Mello napisał:
> 
>     Hello!
>      
>     I need to execute a dynamic query and capture your result in a
>     integer variable.
>      
>     I´m using the statement "EXECUTE string", but I don´t obtain to
>     capture the result of dynamic query.
>           v_count:= EXECUTE v_query;

Documentation:
19.5.4. Executing dynamic queries

"The results from SELECT queries are discarded by EXECUTE, and SELECT 
INTO is not currently supported within EXECUTE. So, the only way to 
extract a result from a dynamically-created SELECT is to use the 
FOR-IN-EXECUTE form described later."

Regards,
Tomasz Myrta

Re: Executing dynamic queries (EXECUTE)

От
"Carla Mello"
Дата:
Hello Tomasz,

I´m going to study the FOR-IN-EXECUTE statement and to try again.

Thanks,
Carla Mello

----- Original Message -----
From: "Tomasz Myrta" <jasiek@klaster.net>
To: "Carla Mello" <carla.mello@widesoft.com.br>
Cc: "Lista dyskusyjna pgsql-sql" <pgsql-sql@postgresql.org>
Sent: Sunday, February 01, 2004 5:43 PM
Subject: Re: [SQL] Executing dynamic queries (EXECUTE)


> Dnia 2004-01-27 16:25, Użytkownik Carla Mello napisał:
> >
> >     Hello!
> >
> >     I need to execute a dynamic query and capture your result in a
> >     integer variable.
> >
> >     I´m using the statement "EXECUTE string", but I don´t obtain to
> >     capture the result of dynamic query.
> >           v_count:= EXECUTE v_query;
>
> Documentation:
> 19.5.4. Executing dynamic queries
>
> "The results from SELECT queries are discarded by EXECUTE, and SELECT
> INTO is not currently supported within EXECUTE. So, the only way to
> extract a result from a dynamically-created SELECT is to use the
> FOR-IN-EXECUTE form described later."
>
> Regards,
> Tomasz Myrta