Hi All,

HQL does not support sub query after from. I do not need this feature in most cases.
However, when I check total count of a report query, I have to write a hql like:


Does hibernate provides any way to achieve it?

Is query.list().size() not sufficient? If not (e.g. if you want to get the count before doing the real query), then just use two different queries: a "select a, b, c where ...", and a "select count(*) where ...".

Yes, I want get the count before doing the real query. However, "select count(*) where" can not meet all cases.
For example. there are three records:
1. a1, b1, c1
2. a1, b1, c2
3. a1, b2, c1
The count result I wanted is:
select count(*) from (Select distinct A, B, C) = 3
select count(*) from (Select distinct A, B) = 2
select count(*) from (Select distinct A) = 1

You will need separate queries for those. They'll look like "select count(distinct a, b, c) where ...", "select count(distinct a, b) where ...", etc.

Oh, does Hibernate support "select count(distinct a, b) from ... where ..."?
How to do it? I have tried in my application with Oracle.
count(distinct a) is okay. But count(distinct a, b) is illegal.
The error message is:
org.hibernate.hql.ast.QuerySyntaxException: expecting CLOSE, found ',' near line 1, column 32 [select count(distinct t.company, t.id) as mycount from ecv.dt.po.Topic t]

Yep, I see that problem. Try it with group by: "select distinct c where ... group by a, b", "select distinct b where ... group by a", etc.

Yeah, group by is another choice.
I will test the performance of group by count later. If it is acceptable, we will apply it.