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SQL IS NOT NULL Function

Quick summary: The SQL IS NOT NULL operator filters rows where a column contains a non-NULL value.

SQL IS NOT NULL Syntax 

expression IS NOT NULL
SQL

SQL IS NOT NULL Basic examples 

SELECT * FROM users WHERE email IS NOT NULL;
SQL
Output:
Users with email set

Filters out rows with NULL values.

SQL IS NOT NULL Real-world usage 

SELECT * FROM orders WHERE shipped_at IS NOT NULL;
SQL
Output:
Shipped orders

Finds completed or processed records.

SQL IS NOT NULL Edge cases 

SELECT * FROM users WHERE phone <> NULL;
SQL
Output:
No rows

NULL cannot be compared using operators.

SQL IS NOT NULL Common mistakes

Using != NULL

NULL comparisons must use IS NOT NULL.

Incorrect
WHERE email != NULL
Correct
WHERE email IS NOT NULL

Use IS NOT NULL explicitly.

SQL IS NOT NULL Frequently Asked Questions

What does IS NOT NULL do in SQL?

Checks if a value is not NULL.

Use case of IS NOT NULL?

Filtering existing values.

Syntax?

column IS NOT NULL.

Common mistake?

Using != NULL instead.

Opposite operator?

IS NULL.

Used with WHERE?

Yes.

Performance?

Depends on indexes.

Handles NULL logic?

Yes.

Used in joins?

Yes.

Alternative?

COALESCE.

Used in data validation?

Yes.

Best practice?

Use explicit NULL checks.

SQL IS NOT NULL Related SQL Keywords