Common SQL Commands Cheat Sheet
Here’s a list of common SQL commands, grouped by purpose — these are the ones you’ll use most often when working with relational databases like MySQL, PostgreSQL, SQL Server, or SQLite.
🧱 1. Database & Table Management
| Purpose |
Command |
Example |
| Create a new database |
CREATE DATABASE |
sql CREATE DATABASE shop_db; |
| Delete a database |
DROP DATABASE |
sql DROP DATABASE shop_db; |
| Use a database |
USE |
sql USE shop_db; |
| Create a new table |
CREATE TABLE |
sql CREATE TABLE users ( id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(100), email VARCHAR(255) UNIQUE, created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ); |
| Delete a table |
DROP TABLE |
sql DROP TABLE users; |
| Modify table structure |
ALTER TABLE |
sql ALTER TABLE users ADD COLUMN age INT; |
| Rename table |
RENAME TABLE |
sql RENAME TABLE users TO customers; |
📋 2. Data Manipulation (CRUD)
| Operation |
Command |
Example |
| Insert data |
INSERT INTO |
sql INSERT INTO users (name, email) VALUES ('John Doe', 'john@example.com'); |
| Read data |
SELECT |
sql SELECT id, name, email FROM users; |
| Update data |
UPDATE |
sql UPDATE users SET name = 'Jane Doe' WHERE id = 1; |
| Delete data |
DELETE |
sql DELETE FROM users WHERE id = 1; |
🔍 3. Filtering & Sorting
| Purpose |
Command |
Example |
| Filter rows |
WHERE |
sql SELECT * FROM users WHERE age > 18; |
| Combine multiple conditions |
AND, OR |
sql SELECT * FROM users WHERE age > 18 AND country = 'US'; |
| Sort results |
ORDER BY |
sql SELECT * FROM users ORDER BY created_at DESC; |
| Limit number of rows |
LIMIT |
sql SELECT * FROM users LIMIT 10; |
| Eliminate duplicates |
DISTINCT |
sql SELECT DISTINCT country FROM users; |
🔗 4. Joining Tables
| Type |
Description |
Example |
INNER JOIN |
Only matching rows |
sql SELECT users.name, orders.id FROM users INNER JOIN orders ON users.id = orders.user_id; |
LEFT JOIN |
All from left, even if no match |
sql SELECT users.name, orders.id FROM users LEFT JOIN orders ON users.id = orders.user_id; |
RIGHT JOIN |
All from right, even if no match |
sql SELECT users.name, orders.id FROM users RIGHT JOIN orders ON users.id = orders.user_id; |
FULL JOIN |
All rows from both sides (if supported) |
sql SELECT users.name, orders.id FROM users FULL JOIN orders ON users.id = orders.user_id; |
📊 5. Aggregation & Grouping
| Purpose |
Command |
Example |
| Count rows |
COUNT() |
sql SELECT COUNT(*) FROM users; |
| Sum values |
SUM() |
sql SELECT SUM(amount) FROM orders; |
| Average |
AVG() |
sql SELECT AVG(age) FROM users; |
| Minimum / Maximum |
MIN(), MAX() |
sql SELECT MIN(price), MAX(price) FROM products; |
| Group results |
GROUP BY |
sql SELECT country, COUNT(*) FROM users GROUP BY country; |
| Filter groups |
HAVING |
sql SELECT country, COUNT(*) FROM users GROUP BY country HAVING COUNT(*) > 10; |
⚙️ 6. Other Useful Commands
| Purpose |
Command |
Example |
| Rename a column result |
AS |
sql SELECT name AS full_name FROM users; |
| Combine query results |
UNION |
sql SELECT name FROM customers UNION SELECT name FROM suppliers; |
| Check structure |
DESCRIBE |
sql DESCRIBE users; |
| Comment |
-- (single line) / /* ... */ (multi-line) |
sql -- This is a comment |