Oracle PL/SQL/Data Type/IS NULL Value

If value IS NULL, raise exception

 
SQL>
SQL> DECLARE
  2     lv_general_excep EXCEPTION;
  3  BEGIN
  4     IF NULL IS NULL THEN
  5        RAISE lv_general_excep;
  6     ELSE
  7        -- Process Logic
  8        NULL;
  9     END IF;
 10  EXCEPTION
 11     WHEN lv_general_excep THEN
 12        NULL;
 13  END;
 14  /
PL/SQL procedure successfully completed.
SQL>

The IS NULL operator in action

SQL>
SQL> -- The IS NULL operator in action.
SQL> SET SERVEROUTPUT ON
SQL> DECLARE
  2     test  INTEGER;
  3  BEGIN
  4     --the variable TEST is currently null because
  5     -- a value hasn"t been assigned to it yet.
  6     IF test IS NULL THEN
  7       DBMS_OUTPUT.PUT_LINE("The variable TEST is null.");
  8     END IF;
  9     --Assign a value to TEST and display it.
 10     test := 1;
 11     DBMS_OUTPUT.PUT_LINE("TEST = " || TO_CHAR(test));
 12     --Test is no longer null because a value has been assigned to it.
 13     IF test IS NOT NULL THEN
 14          DBMS_OUTPUT.PUT_LINE("The variable TEST is NOT null.");
 15     END IF;
 16  END;
 17  /
The variable TEST is null.
TEST = 1
The variable TEST is NOT null.
PL/SQL procedure successfully completed.
SQL>