Oracle 11g Release 2

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CREATE TABLE employees (
  id     NUMBER PRIMARY KEY,
  salary NUMBER,
  bonus  NUMBER,
  total  NUMBER GENERATED ALWAYS AS ( salary + COALESCE( bonus, 0 ) )
)
INSERT INTO employees ( id, salary, bonus )
  SELECT 1, 100, 10   FROM DUAL UNION ALL
  SELECT 2, 100, NULL FROM DUAL;
2 rows affected

SELECT * FROM employees;


ID
SALARY
BONUS
TOTAL


1
100
10
110

2
100
null
100