Sql Programming Tutorials, Guides & Best Practices

Indexes are crucial for speeding up data retrieval operations. They work like a table of contents in a book, allowing the database to find data quickly without scanning the entire table.

CREATE INDEX idx_user_id ON users(user_id);

SELECT name FROM employees_us
UNION ALL
SELECT name FROM employees_uk;

Window functions calculate values across a set of rows related to the current row without collapsing rows into groups.