Multiple permissions can apply to the same query, because the system catalog is scanned for all possible permissions that apply. Generally, this means the broadest grant applies. The hierarchy of evaluation is described in more detail below, but the hierarchy is generally not something the DBA needs to formally consider.

For example, assume that grants have been created to allow all permissions on the employee table to public, and that a grant has been created to allow a particular user, Susan, the select privilege on the employee table. Susan, as part of the public, can perform all operations on the employee table, even though her individual grant was only for select permission.