INSERT, UPDATE, DELETE

These are the write operations in SQL: creating, changing, and removing data.

-- INSERT: add new row
INSERT INTO users (name, email, age)
VALUES ('Daniel', 'daniel@example.com', 20);

-- UPDATE: change existing row
UPDATE users
SET age = 21
WHERE id = 1;

-- DELETE: remove row
DELETE FROM users
WHERE id = 1;

-- CAREFUL: DELETE without WHERE deletes everything!