Declare vKIOTable       varchar2(50);
    sSql            varchar2(4000);
    crs             sys_refcursor;
Begin
...
 
    sSql:='' ||
        'SELECT ' ||
                    'cl.ID                                                            AS CLIENTID  ' ||                                  
                    ',nvl(cl.c_inn, ' || vKIOTable || '.c_kio)                        AS INN ' ||     
					..........
          'FROM     Z#CLIENT cl ' || 
					...........
         'WHERE     1 = 1' ;
 
    open crs for sSql ;

    :crsout:=crs;
END;