ORACLE SQL function that can be used in the where part of a select statement

I would like to create a function that can be used in the where part of a select statement. Like this:

select 'x' from table where addNumber(4,3)=7;

I know how to do this in MS SQL, but I would like to do this Oracle SQL. How can I do this?

From stackoverflow

• You need to write a PL/SQL function...

  CREATE OR REPLACE FUNCTION addNumber(firstParam  IN NUMBER,
                                       secondParam IN NUMBER)
  RETURN NUMBER
  IS 
  BEGIN
     RETURN firstParam + secondParam;
  END;
  /
  

  ...run this into the scheam you're using (probably using SQL*Plus) and then call it as you did in your SQL statement above.

  gyurisc : Thanks for the quick answer