What is the difference between using subqueries and joining tables via JOIN in SQL?

Subqueries and JOINs are two methods of combining data from multiple tables in SQL, but they work differently:

• JOIN combines rows from two or more tables based on a related column. It is usually more efficient and readable when you need to retrieve combined data.

• Subquery is a nested query whose result is used in the main query. Subqueries can return a single value, a set of values, or a table, and are often used for filtering or calculations.

Example:

-- JOIN
SELECT orders.id, customers.name
FROM orders
JOIN customers ON orders.customer_id = customers.id;

-- Subquery
SELECT id, name
FROM customers
WHERE id IN (SELECT customer_id FROM orders);

Overall, JOINs are better for combining data, while subqueries are used for filtering or when the logic is more complex. Sometimes, subqueries can be less performant, but it depends on the specific case and the database optimizer.