Using package constant in SQL

Question

I am trying to use a package constant in a query as follows:
SELECT field1 FROM table t WHERE CEIL(sysdate - t.field2) > schema.package.constant
field1 is a name
field2 is a timestamp
constant is an integer indicating the expiration time in days
basically I am trying to find all expired items.
I get the error "ORA-06553: PLS-221: 'constant' is not a procedure or is undefined" on this query.
I use this same query as a cursor in the package itself with no errors.

Answer 1

Unfortunately you cannot directly use package global variables in select statements like this.
One workaround is to use bind variables for that:
<p>
SQL> CREATE OR REPLACE PACKAGE pkg
AS
   myconstant   VARCHAR (20) := 'This is my constant';
END pkg;
Package created.
SQL> VAR myconstant  VARCHAR2 (20)
SQL> EXEC :myconstant :=  pkg.myconstant
PL/SQL procedure successfully completed.
SQL> SELECT :myconstant
  FROM DUAL
:MYCONSTANT                                                                    
This is my constant