This tutorial shows you how to create relationships between two columns from different tables. Relationships allow you to use the information on one table to filter the information on another table.
Say, for example, you have two tables, one with purchase orders and one with customer demographics. Both tables have a field which is labeled “cust_id” which contains a unique id for each customer. If you create a relationship between these two fields, you will be able to filter purchase orders against information like customer age which is contained in the customer demographics table but is not present in the purchase orders table.