1
SQLIntermediate#joins
SQLBeginner#fundamentals
What are DDL, DML, DQL, DCL and TCL?
DDL defines structure (CREATE, ALTER, DROP, TRUNCATE). DML changes data (INSERT, UPDATE, DELETE). DQL reads data (SELECT). DCL manages permissions (GRANT, REVOKE). TCL controls transactions (COMMIT, ROLLBACK, SAVEPOINT).
Example
ALTER TABLE users ADD phone VARCHAR(15); -- DDL UPDATE users SET phone = '99999' WHERE id = 1; -- DML GRANT SELECT ON users TO analyst; -- DCL ROLLBACK TO SAVEPOINT sp1; -- TCL