Re: Dynamic procedure execution - Mailing list pgsql-general

On 12/28/20 10:34 PM, Muthukumar.GK wrote:

Pleas do not top post, the style on this list is bottom/inline posting.
> Hi Adrian Klaver,
> 
> Sorry for typo mistake. Instead of writing lengthy query, I had written 
> it simple. Actually my main concept is to bring result set with multiple 
> rows (using select query) with help of dynamic query.
> 
> When calling that procedure in Pgadmin4 window, simply getting the 
> message as ‘ CALL     Query returned successfully in 158 msec’.
> 
> FYI, I have implemented simple dynamic query for UPDATE and DELETE rows. 
> It is working fine without any issues.
> 
> Please let me know is there any way of getting result set using dynamic 
> query.
> 
> _Issue with dynamic select:-_
> 
> __
> 
> CREATE OR REPLACE Procedure sp_select_dynamic_sql(
> 
>                  keyvalue integer)
> 
>      LANGUAGE 'plpgsql'
> 
> AS $BODY$
> 
> Declare v_query text;
> 
> BEGIN
> 
>                  v_query:= 'select * from Los_BankInfo '
> 
>          || ' where pk_id = '
> 
>          || quote_literal(keyvalue);
> 
>                  execute v_query;
> 
>                  END;
> 
> $BODY$;
> 
> _Execuion__ of Proc:-_
> 
> CALL sp_select_dynamic_sql (11);
> 
> _Output:-_
> 
> CALL
> 
> Query returned successfully in 158 msec.

See here:

https://www.postgresql.org/docs/current/plpgsql-control-structures.html#PLPGSQL-STATEMENTS-RETURNING-PROCEDURE

"
42.6.2. Returning from a Procedure

A procedure does not have a return value. A procedure can therefore end 
without a RETURN statement. If you wish to use a RETURN statement to 
exit the code early, write just RETURN with no expression.

If the procedure has output parameters, the final values of the output 
parameter variables will be returned to the caller.
"

So use a function and follow the docs here:

https://www.postgresql.org/docs/current/plpgsql-control-structures.html#PLPGSQL-STATEMENTS-RETURNING

in particular:

"42.6.1.2. RETURN NEXT and RETURN QUERY"

> 
> _Working fine with Dynamic UPDATE and DELETE Statement :-_
> 
> __
> 
> _UPDATE:-_
> 
> __
> 
> CREATE OR REPLACE Procedure sp_Update_dynamic_sql(
> 
>                  newvalue varchar(10),
> 
>                  keyvalue integer)
> 
>      LANGUAGE 'plpgsql'
> 
> AS $BODY$
> 
> Declare v_query text;
> 
> BEGIN
> 
>                  v_query:= 'update Los_BankInfo set approverid'
> 
>          || ' = '
> 
>          || quote_literal(newvalue)
> 
>          || ' where pk_id = '
> 
>          || quote_literal(keyvalue);
> 
>          execute v_query;
> 
>                  END;
> 
> $BODY$;
> 
> --CALL sp_Update_dynamic_sql (john,10);
> 
> _DELETE:-_
> 
> __
> 
> CREATE OR REPLACE Procedure sp_Delete_dynamic_sql(
> 
>                  keyvalue integer)
> 
>      LANGUAGE 'plpgsql'
> 
> AS $BODY$
> 
> Declare v_query text;
> 
> BEGIN
> 
>                  v_query:= 'delete from Los_BankInfo '
> 
>          || ' where pk_id = '
> 
>          || quote_literal(keyvalue);
> 
>                  execute v_query;
> 
>                  END;
> 
> $BODY$;
> 
> --CALL sp_Delete_dynamic_sql(10);
> 
> 
> 
> Regards
> 
> Muthu
> 
> 
> On Mon, Dec 14, 2020, 8:54 PM Adrian Klaver <adrian.klaver@aklaver.com 
> <mailto:adrian.klaver@aklaver.com>> wrote:
> 
>     On 12/13/20 9:59 PM, Muthukumar.GK wrote:
>      > Hi team,
>      >
>      > When I am trying to implement belwo dynamic concept in postgreSql,
>      > getting some error. Kindly find the below attached program and
>     error.
>      > Please advise me what is wrong here..
>      >
>      > CREATE OR REPLACE PROCEDURE DynamicProc()
>      >
>      > AS $$
>      >
>      > DECLARE v_query TEXT;
>      >
>      > C1 refcursor := 'result1';
>      >
>      > begin
>      >
>      > v_query := '';
>      >
>      > v_query := ' OPEN C1 FOR SELECT * FROM public."Bankdetails"';
>      >
>      > EXECUTE (v_query);
>      >
>      > END;
>      >
>      > $$
>      >
>      > Language plpgsql;
>      >
>      >   Calling procedure :-
>      >
>      > --------------------------------
>      >
>      > CALL DynamicProc();
>      >
>      > FETCH ALL IN "result1";
>      >
>      >
>      > Error :-
>      >
>      > --------------
>      >
>      > ERROR: syntax error at or near "OPEN"
>      >
>      > LINE 1: OPEN C1 FOR SELECT * FROM public."Los_BankInfo" ^
>      >
>      > QUERY: OPEN C1 FOR SELECT * FROM public."Los_BankInfo"
>      >
>      > CONTEXT: PL/pgSQL function dynamicproc() line 9 at EXECUTE SQL
>     state: 42601
> 
>     Two things:
> 
>     1) The error is from a different version of the procedure then the
>     code.
>     The table name is different. Can't be sure that this is the only
>     change.
>     So can you synchronize your code with the error.
> 
>     2) Take a look here:
> 
>     https://www.postgresql.org/docs/12/plpgsql-cursors.html
>     <https://www.postgresql.org/docs/12/plpgsql-cursors.html>
> 
>     42.7.2. Opening Cursors
> 
>     For why OPEN is plpgsql specific and how to use it.
> 
>      >
>      >
>      > Regards
>      >
>      > Muthukumar.gk
>      >
> 
> 
>     -- 
>     Adrian Klaver
>     adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com