What is NULL in SQL and how is it handled?

NULL represents the absence of a value in a column. It is not the same as an empty string or

zero.

• Handling NULL:
• To check for NULL, use IS NULL or IS NOT NULL.
• To handle NULL in queries, use COALESCE() (returns the first non-NULL

value) or IFNULL().

Example:

SELECT Name, IFNULL(Salary, 0) FROM Employees;