HQL的經常使用語句

Session session = HibernateSessionFactory.getSession();
  /##
   # 經過HQL語句查詢表中的sex字段，distinct是不容許有重複值
   # ---給表中增長SEX字段後必須在xml映射文件以及實體類種增長屬性
   # SQL="select distinct sex from admin";
   #/
    /#String hql = "select distinct a.sex from Admin as a ";
    Query query = session.createQuery(hql);
    List list = query.list();
    Iterator iter = list.iterator();
    while(iter.hasNext()){
    //它不是一個對象，因此只許迭代打印出集合的數據
      System.out.println(iter.next());
    }#/
    /##
     # Count查詢所有的記錄數據
     # SQL="select count(#) from admin";
     #
     #/
    /##
     #  avg查詢所有年齡的平均數,注意只能求int型的參數
     # SQL="select avg(age) from admin";
     # HQL="select avg(a.age) from Admin as a";
     #/
    /#String hql = "select count(#) from Admin as a";
    Query query = session.createQuery(hql);
    List list = query.list();
    Iterator iter = list.iterator();
    while(iter.hasNext()){
      System.out.println(iter.next());
    }#/
    /##
     # 帶where 條件的HQL
     # 更新刪除 HQL
     # update Admin set name="李四" where aid="6"
     # delete Admin where name="李四";
     #  1.HQL="from Admin a where(a.age/10=3)";
     #  2.HQL="from Admin a where(a.age>20) and (a.aname='趙六')"
     #  3.is null或者is not null判斷數據是否爲空
     #   HQL="from Admin a where a.name is not null";
     #  4.between and 測試字段是否在指定的範圍內
     #   HQL="from Admin a where a.aid between 5 and 9";
     #  5.in或者not in來測試字段是否在指定的集合中
     #   HQL="from Admin a where a.name in('張三','李四')"
     #  6.like或者not like進行模糊條件查詢
     #   HQL="from Admin a where a.name like'張%'";
     #  7.order by 進行排序
     #   HQL="from Admin a order by a.age";
     #  8.desc 反排序
     #   HQL = "from Admin a order by a.age desc";
     #  9.同時指定兩個以上的排列方式，先按age反排序，如age相同再按name順序排列
     #   HQL="from Admin a order by a.age desc,a.aname";
     #  10.按指定的字段依據相同的內容分組,取出性別爲男或者女的平均年齡
     #   HQL="select a.sex,avg(a.age) from Admin a group by a.sex";
     #  11.只將平均大於20的數據分組顯示出來
     #   HQL="select a.sex,avg(a.age) from Admin a group by a.sex" having avg(a.age)>20;
     #
     #/
    String hql = "from Admin as a where a.aname=?";
    Query query = session.createQuery(hql);
    query.setString(0, "錢七");
    List list = query.list();
    Iterator iter = list.iterator();
    while(iter.hasNext()){
      Admin admin = (Admin) iter.next();
      System.out.println(admin.getAname());
    }
  /##
   # 分頁操做
   #setFirstResult從第幾行開始取數據
   #setMaxResults取多少行數據
   #/
    String sql = "from Admin as a";
    Query q = session.createQuery(sql);
    q.setFirstResult(0);
    q.setMaxResults(3);
    List l = q.list();
    Iterator i = l.iterator();
    while(i.hasNext()){
      Admin a = (Admin)i.next();
      System.out.println(a.getAname()+"--"+a.getSex()+"--"+a.getAge());
    }
  }