HQL不支持UNION

javax.servlet.ServletException: unexpected token: ( near line 1, column 1 [( select emp from com.neusoft.talentbase.common.business.organization.model.assignedjob.AssignedJobPO a,com.neusoft.talentbase.common.business.staffing.common.po.EmployeePO emp  where a.oid=emp.jobID and a.leaderLevel in ('0','1') and a.unitPO.oid=1738419 and a.status='1' and emp.status='1' and emp.employeeStatus in ('2','5','11','7') ) union ( select e from com.neusoft.talentbase.common.business.organization.model.assignedjob.AssignedJobPO a,com.neusoft.talentbase.common.business.staffing.common.po.EmployeePO e,com.neusoft.talentbase.staffing.model.parttime.ParttimePO p  where    a.oid=p.jobID  and e.oid=p.employee  and a.leaderLevel in ('0','1')  and a.unitPO.oid= 1738419 and a.status='1'  and e.status='1'  and p.status='1'  and e.employeeStatus in ('2','5','11','7') )]
	org.apache.struts.action.RequestProcessor.processException(RequestProcessor.java:516)
	org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:423)
	org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:226)
	com.neusoft.talentbase.framework.core.strutsextension.TbRequestProcessor.process(TbRequestProcessor.java:80)
	org.apache.struts.action.ActionServlet.process(ActionServlet.java:1164)
	org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:397)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
	com.neusoft.report.sample.security.LoginUserFilter.doFilter(LoginUserFilter.java:49)
	com.neusoft.talentbase.framework.core.usercontext.UserContextFilter.doFilter(UserContextFilter.java:82)
	com.neusoft.talentbase.framework.core.filter.CharsetEncodingFilter.doFilter(CharsetEncodingFilter.java:55)

HQL语句：

( select emp from AssignedJobPO a,EmployeePO emp  where a.oid=emp.jobID and a.leaderLevel in ('0','1') and a.unitPO.oid=1738419 and a.status='1' and emp.status='1' and emp.employeeStatus in ('2','5','11','7') )

union 

   ( select e from AssignedJobPO a,EmployeePO e,ParttimePO p  where    a.oid=p.jobID  and e.oid=p.employee  and a.leaderLevel in ('0','1')  and a.unitPO.oid= 1738419 and a.status='1'  and e.status='1'  and p.status='1'  and e.employeeStatus in ('2','5','11','7') )

 

原来HQL不支持UNION操作，因此会报错。

推荐 1，用视图，2，用两个简单的查询。

 

下面是stackoverflow上面的一个人的留言：

You could use id in (select id from ...) or id in (select id from ...)

e.g. instead of non-working

from Person p where p.name="Joe"
union
from Person p join p.children c where c.name="Joe"

you could do

from Person p 
  where p.id in (select p1.id from Person p1 where p1.name="Joe") 
    or p.id in (select p2.id from Person p2 join p2.children c where c.name="Joe");

At least using MySQL, you will run into performance problems with the later though. It's sometimes easier to do a poor man's join on two queries instead:

// use set for uniqueness
Set<Person> people = new HashSet<Person>((List<Person>) query1.list());
people.addAll((List<Person>) query2.list());
return new ArrayList<Person>(people);

It's often better to do two simple queries than one complex one.

EDIT:

to give an example, here is the EXPLAIN output of the resulting MySQL query from the subselect solution:

mysql> explain 
  select p.* from PERSON p 
    where p.id in (select p1.id from PERSON p1 where p1.name = "Joe") 
      or p.id in (select p2.id from PERSON p2 
        join CHILDREN c on p2.id = c.parent where c.name="Joe") \G
*************************** 1. row ***************************
           id: 1
  select_type: PRIMARY
        table: a
         type: ALL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: 247554
        Extra: Using where
*************************** 2. row ***************************
           id: 3
  select_type: DEPENDENT SUBQUERY
        table: NULL
         type: NULL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: NULL
        Extra: Impossible WHERE noticed after reading const tables
*************************** 3. row ***************************
           id: 2
  select_type: DEPENDENT SUBQUERY
        table: a1
         type: unique_subquery
possible_keys: PRIMARY,name,sortname
          key: PRIMARY
      key_len: 4
          ref: func
         rows: 1
        Extra: Using where
3 rows in set (0.00 sec)

Most importantly, 1. row doesn't use any index and considers 200k+ rows. Bad! Execution of this query took 0.7s wheres both subqueries are in the milliseconds.