Logical Operators

Logical operators let you combine multiple conditions in a WHERE clause, making your filters more flexible and precise.

The AND operator filters rows where all conditions must be true.

Copy
SELECT name, membership_type
FROM library_members
WHERE membership_type = 'student' AND has_overdue_books = 'no';

This query returns students who do not have any overdue books.

The OR operator filters rows where at least one condition is true.

Copy
SELECT name, number_of_books
FROM library_members
WHERE membership_type = 'guest' OR number_of_books > 3;

This query returns either guests or anyone with more than 3 books checked out.

The NOT operator filters out rows where the condition is true, returning only those that do not match.

Copy
SELECT name
FROM library_members
WHERE NOT has_overdue_books = 'yes';

This query returns only members who do not have overdue books.