SQL — Update

Basic UPDATE

UPDATE users
SET age = 31
WHERE name = 'Alice';

Multiple columns

UPDATE users
SET age = 31, email = 'alice_new@example.com'
WHERE name = 'Alice';

UPDATE with conditions

UPDATE users
SET status = 'inactive'
WHERE last_login < '2025-01-01';

UPDATE with JOIN

-- MySQL
UPDATE users u
JOIN orders o ON u.id = o.user_id
SET u.last_order = o.order_date
WHERE o.total > 100;

-- PostgreSQL
UPDATE users
SET last_order = orders.order_date
FROM orders
WHERE users.id = orders.user_id
AND orders.total > 100;

UPDATE with subquery

UPDATE users
SET status = 'premium'
WHERE id IN (
  SELECT user_id FROM orders WHERE total > 1000
);

UPDATE with default

UPDATE users
SET phone = DEFAULT
WHERE id = 1;

Returning updated data

-- PostgreSQL
UPDATE users SET age = 31
WHERE name = 'Alice'
RETURNING id, name, age;

Mini Practice

Write SQL code that:

1. Updates a single column
2. Updates multiple columns
3. Uses a WHERE condition
4. Updates with a subquery

Up Next

In the next lesson, you'll learn about Delete — removing data.