The CData Excel Add-In for Amazon Marketplace supports standard SQL joins like the following examples.

Inner Join

An inner join selects only rows from both tables that match the join condition:

SELECT c.SellerOrderId, o.SellerSKU, o.NumberOfItems, o.QuantityShipped FROM Orders c INNER JOIN OrderItems o ON c.AmazonOrderId = o.AmazonOrderId

Left Join

A left join selects all rows in the FROM table and only matching rows in the JOIN table:

 SELECT c.SellerOrderId, o.SellerSKU, o.NumberOfItems, o.QuantityShipped FROM Orders c LEFT JOIN OrderItems o ON c.AmazonOrderId = o.AmazonOrderId