HQL supports two forms of association joining:
The queries shown in the previous section all use the
explicit form, that is, where the join keyword is explicitly used in the from clause. This is the recommended form.
implicit form does not use the join keyword. Instead, the associations are "dereferenced" using dot-notation.
implicit joins can appear in any of the HQL clauses.
implicit join result in inner joins in the resulting SQL statement.
from Cat as cat where cat.mate.name like '%s%'