In my opinion if we want to allow aliases overriding the scope should follows the Java rules, it's easier to understand for a Java developer and the second query should just be considered a bad written one.
On 7 October 2015 at 15:27, Steve Ebersole <st...@hibernate.org> wrote: > > > > > Here the aliases `c` do infringe. In the subquery, we don't really > know > > > which reference the `c` alias should resolve to. We *could* here > > assuming > > > that the subquery is uncorrelated. Bu without this rule we really > would > > > not know that the subquery is correlated > > > > Out of curiosity, Couldn't for this case assume that the second alias > > overrides the first. > > This might cause some hard to spot errors, though. > > > > The issue really is for cases of correlated subqueries (where the subquery > refers to the outer query). So imagine a query such as: > > select ... > from Salesperson s > where exists ( > select count(*) > from Sale s2 > where s.id = s2.salesperson.id ... > group by s2.salesperson.id > having count(*) > :sales > ) > > So here the predicate `s.id = s2.salesperson.id` defines a correlation > beween hthe queries. If we allowed the "alias overriding", it is quite > possible for the user to (mistakenly) write this query as: > > select ... > from Salesperson s > where exists ( > select count(*) > from Sale s > where s.id = s.salesperson.id ... > group by s.salesperson.id > having count(*) > :sales > ) > > Which validates fine, but is not *really* what they meant and would not > return what they are looking for. > _______________________________________________ > hibernate-dev mailing list > hibernate-dev@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/hibernate-dev > _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
