MySQL IS NULL Operator
Introduction
To test whether a value is NULL or not, we use the IS NULL operator.
Here is the basic syntax of the IS NULL operator:
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SELECT column_names
FROM table_name
WHERE column_name IS NULL;
If the value is NULL, the expression returns true. Otherwise, it returns false.
To check if a value is not NULL, we use IS NOT NULL operator:
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SELECT column_names
FROM table_name
WHERE column_name IS NOT NULL;
Examples
The following query lists all customers with a NULL value in the “Address” field:
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mysql> SELECT CustomerName, ContactName, Address FROM Customers
-> WHERE Address IS NULL;
+---------------------+--------------+---------+
| CustomerName | ContactName | Address |
+---------------------+--------------+---------+
| Alfreds Futterkiste | Maria Anders | NULL |
+---------------------+--------------+---------+