Webfiltering Fortiguard query - hostname only or full url path ?

I guess this will be helpful to explain the different situations, it's taken from the FortiOS Handbook 5.4.4

Scenario 1: The configuration of the domain name overrides the configuration for the subdirectory. Depending on the URL specified or other aspects of configuration, the configuration of a local or custom category may not take effect. Consider a scenario where you have defined:

[ul]

example.com – local rating as “category 1”, action set to Block

example.com/subdirectory – local rating as “category 2”, action set to Monitor

example.com/subdirectory/page.html – local rating as “category 3”, action set to Warning.[/ul]

If a user browses to “example.com", access will be blocked. If a user browses to example.com/subdirectory, access will also be blocked,even though that address was configured to be part of category2. The configuration of the domain name overrides the configuration for the subdirectory. However, if you configure a specific HTML page differently than the domain name, then that configuration will apply. In this scenario, the user will see a Warning message but will be able to pass through to the page.