NVL, NVL2, COALESCE, NULLIF

NULL Handling Functions

NVL

SELECT first_name, NVL(commission_pct, 0) FROM employees;

NVL2

SELECT first_name, NVL2(commission_pct, 'Has Commission', 'No Commission') FROM employees;

COALESCE

SELECT COALESCE(NULL, NULL, 'default') FROM dual;

NULLIF

SELECT NULLIF(salary, 0) FROM employees;