How can we check for NULL in MySQL query?

With the help of IS NULL operator, we can check for NULL in MySQL queries. We cannot use = (comparison operator) because we know that NULL is not a value. The following example using data from the "Employees" table will demonstrate it -

Example

mysql> Select * from Employee WHERE Salary IS NULL;
+----+-------+--------+
| ID | Name  | Salary |
+----+-------+--------+
| 7  | Aryan | NULL   |
| 8  | Vinay | NULL   |
+----+-------+--------+
2 rows in set (0.00 sec)

The above query uses the IS NULL operator and generates an output with NULL in the salary column.

mysql> Select * from employee where salary = NULL;
Empty set (0.00 sec)

The above query uses = (comparison operator) and therefore produces an empty set because NULL is not a value.

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