There are both inner joins and outer joins. Inner joins, which are also known as equi-joins, are by far the most common. All the queries you have done used an inner join. An inner join retrieves records only when there are equal values (that is, matching data) in the common field in the tables. As you saw, if you have suppliers in one table and merchandise in another, and a common SupplierID in both, you can use an inner join to create a query that matches merchandise data with supplier data. When you create a multitable query, an inner join is the default. If you want to create queries in which only records with matching data are retrieved, you don't have to worry what type of join you're using.