I was looking at HIA: ch 7, pg 262 about how a HQL query would look as a resultant SQL query and was curious if Hibernate generates SQL query as appropriate for the database flavor.

For e.g. if an application needs to support multiple databases would Hibernate require different queries for different databases (e.g. in the case where the different databases have different ways of doing outer joins) ?

HQL and the Criteria API make Hibernate queries database portable. There are more than 20 (or even 25 now) database dialects in the Hibernate distribution.