FULL OUTER JOIN

https://www.w3schools.com/sql/sql_join_full.asp

SELECT 
     Customers.CustomerName, Orders.OrderID
FROM 
     Customers
     FULL OUTER JOIN Orders ON Customers.CustomerID = Orders.CustomerID
ORDER BY 
     Customers.CustomerName;

The FULL OUTER JOIN keyword returns all matching records from both tables whether the other table matches or not. So, if there are rows in “Customers” that do not have matches in “Orders”, or if there are rows in “Orders” that do not have matches in “Customers”, those rows will be listed as well.