15.16. Tips & Tricks

( (Integer) session.createQuery("select count(*) from ....").iterate().next() ).intValue()

( (Integer) session.createQuery("select count(*) from ....").iterate().next() ).intValue()

select usr.id, usr.name
from User as usr
    left join usr.messages as msg
group by usr.id, usr.name
order by count(msg)

select usr.id, usr.name
from User as usr
    left join usr.messages as msg
group by usr.id, usr.name
order by count(msg)

from User usr where size(usr.messages) >= 1

from User usr where size(usr.messages) >= 1

select usr.id, usr.name
from User usr
    join usr.messages msg
group by usr.id, usr.name
having count(msg) >= 1

select usr.id, usr.name
from User usr
    join usr.messages msg
group by usr.id, usr.name
having count(msg) >= 1

select usr.id, usr.name
from User as usr
    left join usr.messages as msg
group by usr.id, usr.name
having count(msg) = 0

select usr.id, usr.name
from User as usr
    left join usr.messages as msg
group by usr.id, usr.name
having count(msg) = 0

Query q = s.createQuery("from foo Foo as foo where foo.name=:name and foo.size=:size");
q.setProperties(fooBean); // fooBean has getName() and getSize()
List foos = q.list();

Query q = s.createQuery("from foo Foo as foo where foo.name=:name and foo.size=:size");
q.setProperties(fooBean); // fooBean has getName() and getSize()
List foos = q.list();

Query q = s.createFilter( collection, "" ); // the trivial filter
q.setMaxResults(PAGE_SIZE);
q.setFirstResult(PAGE_SIZE * pageNumber);
List page = q.list();

Query q = s.createFilter( collection, "" ); // the trivial filter
q.setMaxResults(PAGE_SIZE);
q.setFirstResult(PAGE_SIZE * pageNumber);
List page = q.list();

Collection orderedCollection = s.createFilter( collection, "order by this.amount" ).list();
  Collection counts = s.createFilter( collection, "select this.type, count(this) group by this.type" ).list();

Collection orderedCollection = s.createFilter( collection, "order by this.amount" ).list();
  Collection counts = s.createFilter( collection, "select this.type, count(this) group by this.type" ).list();

( (Integer) session.createQuery("select count(*) from ....").iterate().next() ).intValue();

( (Integer) session.createQuery("select count(*) from ....").iterate().next() ).intValue();