HQL 语句总结

条件查询



1.拼字符串

where条件后面，可以用字符串连接组成条件

String hql = " select s.id, s.name from Student s where s.name like '%1%'";
Query query = session.createQuery(hql);

List list = query.list();

for (Iterator iter=students.iterator(); iter.hasNext();) {
    Object[] obj = (Object[])iter.next();
    System.out.println(obj[0] + "," + obj[1]);
}




2.可以采用 ？来传递参数（索引从0开始）

（1）分开设值

//条件查询，参数索引值从0开始，索引位置。通过setString,setParameter设置参数String hql = "from Users where name=? and passwd=?";

Query query = session.createQuery(hql);

    

//第1种方式

//query.setString(0, "name1");

//query.setString(1, "password1");



//第2种方式

query.setParameter(0, "name1",Hibernate.STRING);

query.setParameter(1, "password1",Hibernate.STRING);

List<Users> list = query.list();



for(Users users : list){

    System.out.println(users.getId());

}




（2）方法链

List students = session.createQuery("select s.id, s.name from Student s

                where s.name like ?")
                    .setParameter(0, "%1%")
                    .list();

for(Iterator iter=students.iterator(); iter.hasNext();) {
    Object[] obj = (Object[])iter.next();
    System.out.println(obj[0] + "," + obj[1]);
}




3.使用 ：参数名称的方式传递参数值

//条件查询，自定义索引名(参数名):username,:password.通过

//setString,setParameter设置参数

String hql = "from Users where name=:username and passwd=:password";

Query query = session.createQuery(hql);



//第1种方式

//query.setString("username", "name1");

//query.setString("password", "password1");



//第2种方式,第3个参数确定类型

query.setParameter("username", "name1",Hibernate.STRING);

query.setParameter("password", "password1",Hibernate.STRING);



//第3种方式

//query = query.setParameter("username", "name1").setParameter

//("password", "password1");



List<Users> list = query.list();



for(Users users : list){

    System.out.println(users.getId());

}




4.支持谓词in，需要使用setParameterList进行参数传递

List students = session.createQuery("select s.id, s.name from Student s

         where s.id in(:myids)")
         .setParameterList("myids", new Object[]{1, 2, 3, 4, 5})
         .list();
  
for (Iterator iter=students.iterator(); iter.hasNext();) {
    Object[] obj = (Object[])iter.next();
    System.out.println(obj[0] + "," + obj[1]);
}




5.在HQL中使用数据库的函数

List students = session.createQuery("select s.id, s.name from Student s

         where date_format(s.createTime, '%Y-%m')=?")
         .setParameter(0, "2010-12")
         .list();
for (Iterator iter=students.iterator(); iter.hasNext();) {
    Object[] obj = (Object[])iter.next();
    System.out.println(obj[0] + "," + obj[1]);
}




6.查询时间段的数据

http://blog.sina.com.cn/s/blog_59c701350100nkuk.html

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
  
List students = session.createQuery("select s.id, s.name from Student s

         where s.createTime between ? and ?")
         .setParameter(0, sdf.parse("2010-12-01 00:00:00"))
         .setParameter(1, sdf.parse("2010-12-31 23:59:59"))
               .list();
for (Iterator iter=students.iterator(); iter.hasNext();) {
    Object[] obj = (Object[])iter.next();
    System.out.println(obj[0] + "," + obj[1]);
}