MySQL — Delete

Basic DELETE

DELETE FROM users WHERE id = 1;

Delete Multiple Rows

DELETE FROM users WHERE age < 18;

Delete All Rows

DELETE FROM users;

DELETE Examples

-- Delete single row
DELETE FROM users WHERE id = 5;

-- Delete with multiple conditions
DELETE FROM orders
WHERE status = 'cancelled' AND created_at < '2023-01-01';

-- Delete with LIMIT
DELETE FROM logs
WHERE created_at < '2022-01-01'
LIMIT 1000;

-- Delete from multiple tables
DELETE users, orders
FROM users
INNER JOIN orders ON users.id = orders.user_id
WHERE users.is_active = FALSE;

WARNING

-- Always use WHERE clause!
DELETE FROM users; -- Deletes ALL rows!

-- Test with SELECT first
SELECT * FROM users WHERE condition;

Best Practices

1. Always use WHERE clause
2. Test with SELECT first
3. Use LIMIT for large deletions
4. Consider soft deletes (is_active flag)
5. Backup before bulk deletes

Mini Practice

Write MySQL code that:

1. Deletes a single row
2. Deletes multiple rows
3. Uses LIMIT for deletion
4. Tests with SELECT first

Up Next

Next: Learn about Limiting Results.