如何在 hibernate.ejb 中编写内连接选定表查询

Question

I have a query working fine:

StringBuilder query = new StringBuilder(
        "select o.deviceName, o.deviceOs, o.loginOn, e.username, e.name, e.idNo from LoginHistory o, User e ");
    query.append(" where o.userId = e.userId");
Query q = getEm().createQuery(query.toString());

This createQuery() will go to createQuery() in class org.hibernate.ejb.AbstractEntityManagerImpl .

I want to edit the query to get the last login for each user. The following SQL query can run in a db2 command successfully:

select m1.*, m2.*
from tibs.LoginHistory m1 inner join (
    select userId, max(loginOn) as loginOn from tibs.LoginHistory group by userId
    ) m2
on m1.userId = m2.userId and m1.loginOn = m2.loginOn;

But when I try to apply this in my code above, it will hit QuerySyntaxException: unexpected token: at ( after inner join .

Code is something like:

StringBuilder query = new StringBuilder(
        "select o.deviceName, o.deviceOs, o.loginOn, e.username, e.name, e.cif, e.idNo from LoginHistory o, ECUser e ");
    query.append("inner join (select o2.userId, o2.max(loginOn) as loginOn from LoginHistory group by userId) o2 ");
    query.append("on o.userId = o2.userId and o.loginOn = o2.loginOn");
    query.append(" where o.userId = e.userId");

Is this workable in this way? If yes, what syntax should I use?

Or does Hibernate not accept this, and I need to do it in another way?

Add on** Even I change my query to this, still the same:

StringBuilder query = new StringBuilder(
        "select o.deviceName, o.deviceOs, o.loginOn, e.username, e.name, e.cif, e.idNo from LoginHistory o, ECUser e ");
    query.append("inner join (select o2.userId, o2.max(loginOn) as loginOn from LoginHistory o2 group by userId) ");
    query.append("on o.userId = o2.userId and o.loginOn = o2.loginOn");
    query.append(" where o.userId = e.userId");

Answer 1

I think the inner query should be as follows (note position of o2 ):

(select o2.userId, o2.max(loginOn) as loginOn from LoginHistory o2 group by userId)

Please name variables appropriately to facilitate comprehension.
It would be helpful if o2 was renamed to lh , since it represents LoginHistory entity.

(select lh.userId, lh.max(loginOn) as loginOn from LoginHistory lh group by userId)

Answer 2

You can use the following query:

select o.deviceName, o.deviceOs, o.loginOn, e.username, e.name, e.idNo
from LoginHistory o, User e 
where o.id = (select max(lh.id) from LoginHistory lh where lh.userId = e.userId)