Do Hibernate Projection aliases even work? I could swear it just doesn't. At least, it doesn't do what I would expect it to do.
Here is the java:
return sessionFactory.getCurrentSession()
.createCriteria(PersonProgramActivity.class)
.setProjection(Projections.projectionList()
.add(Projections.alias(Projections.sum("numberOfPoints"), "number_of_points"))
.add(Projections.groupProperty("person.id")))
.setFirstResult(start)
.setFetchSize(size)
.addOrder(Order.desc("numberOfPoints"))
.list();
Here is the SQL that it generates:
select
sum(this_.number_of_points) as y0_,
this_.person_id as y1_
from
PERSON_PROGRAM_ACTIVITY this_
group by
this_.person_id
order by
this_.number_of_points desc
It doesn't seem to use the alias at all. I would think setting the alias would mean that sum(this_.number_of_points)
would be aliased as number_of_points
and not y0_
. Is there some trick I am missing?
Thanks.
You need to give the entire criteria an alias, then you can create other aliases that actually get used. What is strange is that the aliases get turned into y0_
instead of the other way around.
return sessionFactory.getCurrentSession()
.createCriteria(PersonProgramActivity.class, "ppa")
.setProjection(Projections.projectionList()
.add(Projections.alias(Projections.sum("numberOfPoints"), "ppa.numberOfPoints"))
.add(Projections.groupProperty("person.id")))
.setFirstResult(start)
.setFetchSize(size)
.addOrder(Order.desc("ppa.numberOfPoints"))
.list();
Generates the following SQL:
select
sum(this_.number_of_points) as y0_,
this_.person_id as y1_
from
PERSON_PROGRAM_ACTIVITY this_
group by
this_.person_id
order by
this_.y0_ desc
The query should be
return sessionFactory.getCurrentSession()
.createCriteria( PersonProgramActivity.class, "ppa" )
.setProjection(Projections.projectionList()
.add( Projections.alias( Projections.sum( **"ppa.numberOfPoints"** ), **"numberOfPoints"** ) )
.add( Projections.groupProperty( "person.id" ) ) )
.setFirstResult( start )
.setFetchSize( size )
.addOrder( Order.desc( "ppa.numberOfPoints" ) )
.list();
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