Prev Next

PostgreSQL INNER JOIN

An INNER JOIN returns rows that have matching values in both tables. Rows without matches in either table are excluded from the result set.

Example

SELECT c.customer_id, c.first_name, o.order_id
FROM customers c
INNER JOIN orders o ON c.customer_id = o.customer_id;

Best Practices

  • Use INNER JOIN when you only need rows that match in both tables.
  • Consider indexing the join columns for faster lookups.

Key Takeaways

  • INNER JOIN excludes rows with no matching key in the other table.
  • Always specify the join condition with the ON clause.
Prev Next