SQL Cheatsheet
Comprehensive reference for SQL statements, functions, and transactions.
| Keyword | Description | Syntax | Example | Category |
|---|---|---|---|---|
| SELECT | Retrieve data from a table | SELECT columns FROM table [WHERE condition] [ORDER BY column] | SELECT id, name FROM users WHERE age > 18 | DML |
| INSERT | Insert new rows into a table | INSERT INTO table (columns) VALUES (values) | INSERT INTO users (id, name) VALUES (1, "John") | DML |
| UPDATE | Modify existing rows | UPDATE table SET column = value WHERE condition | UPDATE users SET name = "Jane" WHERE id = 1 | DML |
| DELETE | Remove rows from a table | DELETE FROM table WHERE condition | DELETE FROM users WHERE id = 1 | DML |
| CREATE TABLE | Create a new table | CREATE TABLE table_name (column datatype, ...) | CREATE TABLE users (id INT, name VARCHAR(100)) | DDL |
| ALTER TABLE | Modify table structure | ALTER TABLE table_name ADD|DROP|MODIFY column datatype | ALTER TABLE users ADD email VARCHAR(255) | DDL |
| DROP TABLE | Delete a table | DROP TABLE table_name | DROP TABLE users | DDL |
| TRUNCATE TABLE | Delete all rows in a table | TRUNCATE TABLE table_name | TRUNCATE TABLE users | DDL |
| WHERE | Filter rows in a query | WHERE condition | WHERE age > 18 | DML |
| JOIN | Combine rows from multiple tables | INNER|LEFT|RIGHT JOIN table ON condition | INNER JOIN orders ON users.id = orders.user_id | DML |
| GROUP BY | Group rows with same values | GROUP BY column | GROUP BY status | DML |
| ORDER BY | Sort query results | ORDER BY column [ASC|DESC] | ORDER BY created_at DESC | DML |
| COUNT() | Count number of rows | COUNT(*) or COUNT(column) | SELECT COUNT(*) FROM users | Function |
| SUM() | Sum of numeric column | SUM(column) | SELECT SUM(salary) FROM employees | Function |
| AVG() | Average of numeric column | AVG(column) | SELECT AVG(age) FROM users | Function |
| GRANT | Grant privileges to a user | GRANT privilege ON object TO user | GRANT SELECT ON users TO john | DCL |
| REVOKE | Revoke privileges from a user | REVOKE privilege ON object FROM user | REVOKE SELECT ON users FROM john | DCL |
| COMMIT | Commit a transaction | COMMIT | COMMIT; | TCL |
| ROLLBACK | Rollback a transaction | ROLLBACK | ROLLBACK; | TCL |
| SAVEPOINT | Set a savepoint in transaction | SAVEPOINT savepoint_name | SAVEPOINT sp1 | TCL |