Uh-oh. Can this be a typo?
max(teSub.createdTimestamp)
instead of
max(te.createdTimestamp)
in the subquery.
Question
I need to get the latest "version" of a Task object for a given objectUuid. The Task is identified by its objectUuid, taskName and createdTimestamp attributes.
I had the following HQL query:
select new list(te) from " + TaskEntity.class.getName() + " te
where
te.objectUuid = '" + domainObjectId + "' and
te.createdTimestamp = (
select max(te.createdTimestamp) from " + TaskEntity.class.getName() + " teSub
where teSub.objectUuid = te.objectUuid and teSub.taskName = te.taskName
)
which ran and produced the correct results on H2 (embedded) and MySQL. However after installing this code in production to MS SQL Server I get the following error:
An aggregate may not appear in the WHERE clause unless it is in a subquery contained in a HAVING clause or a select list, and the column being aggregated is an outer reference.
I tried to rewrite the query but HQL doesn't seem to support subqueries properly. My latest attempt is something like:
select new list(te) from " + TaskEntity.class.getName() + " te
inner join (
select te2.objectUuid, te2.taskName, max(te2.createdTimestamp)
from " + TaskEntity.class.getName() + " te2
group by te2.objectUuid, te2.taskName
) teSub on
teSub.objectUuid = te.objectUuid and teSub.taskName = te.taskName
where
te.objectUuid = '" + domainObjectId + "'
but of course it fails at the "(" after the join statement.
Since this is a very frequent type of query I cannot believe there is no solution that works with HQL+MSSQL.
Solution
Uh-oh. Can this be a typo?
max(teSub.createdTimestamp)
instead of
max(te.createdTimestamp)
in the subquery.