Choosing the join column

Learn the difference between USING and ON.

Matching column choice

When joining equally named columns, USING is a shortcut. For different names use ON.

SELECT * FROM orders
INNER JOIN customers
  USING (customer_id);

USING works when customer_id is in both tables.

All columns are selected from orders. customers USING is joined, keeping only matching rows.

USING is only for same-named columns. When names differ, ON must be written explicitly.

For example, if both orders and customers have customer_id, you write USING (customer_id); the column then appears only once in the result.

Join using the customer_id column with USING.

Show example solution

SELECT *
FROM orders
INNER JOIN customers
  USING (customer_id);

Add USING

SELECT * FROM orders
INNER JOIN customers
____ (customer_id);

Show answer

SELECT * FROM orders
INNER JOIN customers
USING (customer_id);