create table tempdb.table1 (a int);
create table tempdb.table2 (a int, b int);
insert into tempdb.table1 values ( 1 );
insert into tempdb.table2 values ( 1 , 2 );

create procedure tempdb.test (in_tab_id smallint)
begin
    declare i_crea varchar( 100 );
    declare i_drop varchar( 100 );
    declare i_ins varchar( 100 );
    if ( 1 = 2 ) then
        declare global temporary table table1 (a int);
    end if;
    
    if in_tab_id =  1  then
        set i_crea = 'declare global temporary table table1 (a int) ON COMMIT preserve  ROWS';
    else
        set i_crea = 'declare global temporary table table1 (a int, b int) ON COMMIT preserve  ROWS';
    end if;
    execute immediate i_crea;
p1: begin
        declare c_res cursor with return for
        select * from session.table1;

        if in_tab_id =  1  then
            set i_ins = 'insert into session.table1 select * from tempdb.table1';
        else
            set i_ins = 'insert into session.table1 select * from tempdb.table2';
        end if;
                
        execute immediate i_ins;

        open c_res;
               
   end p1;
end
;

call tempdb.test( 2 )

create procedure dyn_test(stmt varchar( 4000 ))
dynamic result sets  1 
begin
  declare c1 cursor with return for s1;
  prepare s1 from stmt;
  open c1;
end@

call dyn_test('values 1')@

call dyn_test('select tabschema, tabname, colname from syscat.columns fetch first 10 rows only')@