My Procedure isn't working right. It keeps giving me an error create or replace PROCEDURE CHECK_BLACKLIST 
(
  P_EMPLOYEE_USERNAME IN VARCHAR2 
, P_ROWCOUNT OUT NUMBER 
) AS 
BEGIN
  SELECT COUNT(*) INTO P_ROWCOUNT FROM boe_safegaurd WHERE UPPER(employee_username) = UPPER(P_EMPLOYEE_USERNAME);  
END CHECK_BLACKLIST;


Errors

I entered joe@example.com when I ran the procedure. 

ORA-06550: line 5, column 26:
PLS-00352: Unable to access another database 'example.com'
ORA-06550: line 5, column 26:
PLS-00201: identifier 'joe@eample.com' must be declared
ORA-06550: line 5, column 3:
PL/SQL: Statement ignored
Process exited.


when I enter "joe@example.com", I get a similar error

ORA-06550: line 5, column 27:
PLS-00201: identifier 'joe@eample.com' must be declared
ORA-06550: line 5, column 3:
PL/SQL: Statement ignored
You're right. While the procedure executes correctly from SQL or PL/SQL code, somehow SQLDeveloper raises an exception when you invoke the procedure (via the green arrow) and pass anything as input that contains a "@" sign. It's either a peculiar behavior of SQL Developer or a bug.

But executing it directly works fine, also from SQL Developer: