No puedes.
Para que una variable de paquete público se use en una instrucción SQL, debe escribir una función contenedora para exponer el valor al mundo exterior:
SQL> create package my_constants_pkg
2 as
3 max_number constant number(2) := 42;
4 end my_constants_pkg;
5 /
Package created.
SQL> with t as
2 ( select 10 x from dual union all
3 select 50 from dual
4 )
5 select x
6 from t
7 where x < my_constants_pkg.max_number
8 /
where x < my_constants_pkg.max_number
*
ERROR at line 7:
ORA-06553: PLS-221: 'MAX_NUMBER' is not a procedure or is undefined
Crear una función contenedora:
SQL> create or replace package my_constants_pkg
2 as
3 function max_number return number;
4 end my_constants_pkg;
5 /
Package created.
SQL> create package body my_constants_pkg
2 as
3 cn_max_number constant number(2) := 42
4 ;
5 function max_number return number
6 is
7 begin
8 return cn_max_number;
9 end max_number
10 ;
11 end my_constants_pkg;
12 /
Package body created.
Y ahora funciona:
SQL> with t as
2 ( select 10 x from dual union all
3 select 50 from dual
4 )
5 select x
6 from t
7 where x < my_constants_pkg.max_number()
8 /
X
----------
10
1 row selected.
