Most join conditions are based on equality, and so are called equijoins. For example,

SELECT *
FROM Departments JOIN Employees
   ON Departments.DepartmentID = Employees.DepartmentID;

However, you do not have to use equality (=) in a join condition. You can use any search condition, such as conditions containing LIKE, SOUNDEX, BETWEEN, > (greater than), and != (not equal to).

Example

The following example answers the question: For which products has someone ordered more than the quantity in stock?

SELECT DISTINCT Products.Name
FROM Products JOIN SalesOrderItems
ON Products.ID = SalesOrderItems.ProductID
   AND SalesOrderItems.Quantity > Products.Quantity;

For more information about search conditions, see Search conditions.