# FULL OUTER JOIN

A join returning matched rows plus unmatched rows from both sides.

## What is **FULL OUTER JOIN** in a relational database?

**FULL OUTER JOIN** — A join returning matched rows plus unmatched rows from both sides.

```sql
SELECT customer.email, purchase_order.order_id
FROM customer
FULL OUTER JOIN purchase_order
    ON purchase_order.customer_id = customer.customer_id;
```

Level: Apprentice · [More Database terms at this level](https://www.ask-codey.com/glossary/subjects/database/apprentice)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/full-outer-join