A full outer join returns all rows from both tables, including any unmatched rows, whereas an inner join only returns rows that match the join condition between the two tables. For an example of each one, say you had sales data exported from Spotify's Salesforce CRM stored in a datawarehouse which had two tables: sales and spotify_customers. **INNER JOIN:** retrieves rows from both tables where there is a match in the shared key or keys. SELECT * FROM sales INNER JOIN spotify_customers ON sales.customer_id = spotify_customers.id This query will return rows from the sales and spotify_customers tables that have matching customer_id values. Only rows with matching customer_id values will be included in the results. **FULL OUTER JOIN:** retrieves all rows from both tables, regardless of whether there is a match in the shared key or keys. If there is no match, NULL values will be returned for the columns of the non-matching table. Here is an example of a SQL full outer join using the sales and spotify_customers tables: SELECT * FROM sales FULL OUTER JOIN spotify_customers ON sales.customer_id = spotify_customers.id ---