sql if null code example

Example 1: nvl in sql

(NVL) replaces NULL values with same type default
value provided.
For Example = 
Select NVL(commission_percentage, 0)
From Employees;

Example 2: sql is null

Tests for empty (NULL) values.
Example: Returns users that haven’t given a contact number.
SELECT * FROM users
WHERE contact_number IS NULL;

Example 3: sql is not null

The reverse of NULL. Tests for values that aren’t empty / NULL
"Tests for empty (NULL) values.
Example: Returns users that haven’t given a contact number.
SELECT * FROM users
WHERE contact_number IS NULL;"