What is difference between nullif and isnull in sql statme

Question

What is difference between nullif and isnull in sql statment?

Abhay Shanker · Answer

NULLIF: NULLIF ( expression  expression ) It returns a null value if both the expression is equal. NULLIF returns the first expression if both the expression is not equal. ISNULL: ISNULL ( expression  replacement ) Replaces NULL with the specified replacement value. It returns the value of expression if it is not null.