The Exists in table attribute represents that a matching record exists in a joined table in the data warehouse or an auxiliary database. Typically, exists in table attributes are used to exclude records that exist within suppression tables. For example, if a selection rule's resolution level is set to customer, an Exists in table attribute representing customers' existence in a suppression table could be added to the rule as a criterion and set to be excluded. When the rule is run, customers that exist within the suppression table are not counted. The specifics of how the customer and suppression tables are linked are defined by a join.