SQL Commands Cheat Sheet

The most used SQL statements for querying and modifying data

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Querying

SELECT * FROM users;
SELECT name, email FROM users;
SELECT * FROM users WHERE status = 'active';
SELECT * FROM users WHERE created_at > '2026-01-01';
SELECT * FROM users ORDER BY name ASC;
SELECT * FROM users LIMIT 10;

Modifying data

INSERT INTO users (name, email) VALUES ('Jane', 'jane@example.com');
UPDATE users SET status = 'active' WHERE id = 1;
DELETE FROM users WHERE id = 1;

Joins

SELECT users.name, orders.total
FROM users
INNER JOIN orders ON orders.user_id = users.id;

SELECT users.name, orders.total
FROM users
LEFT JOIN orders ON orders.user_id = users.id;

Aggregation

SELECT COUNT(*) FROM users;
SELECT SUM(total) FROM orders;
SELECT AVG(total) FROM orders;
SELECT MAX(total), MIN(total) FROM orders;
SELECT status, COUNT(*) FROM users GROUP BY status;
SELECT status, COUNT(*) AS n FROM users GROUP BY status HAVING n > 10;

Schema

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    email VARCHAR(255) UNIQUE,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
ALTER TABLE users ADD COLUMN age INT;
DROP TABLE users;
CREATE INDEX idx_email ON users (email);