hibernate框架，HQL查询语句大全

HQL是Hibernate Query Language的缩写，提供更加丰富灵活、更为强大的查询能力；HQL更接近SQL语句查询语法。

package test;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;

import bean.Customer;
import utils.HibernateUtils;

public class Hql {

	public static void main(String[] args) {
		//普通的oid查询
		
		//test1();
		//HQL查询
		
		//1.查询表中所有数据
		//test2();
		
		//2.条件查   
		//test3();
		
		//3.分页查
		//test4();
		
		//4.单列查
		//test5();
		
		//5.多列查
		//test6();
		
		//6.投影查询
		//test7();
		
		//7.排序查
		//test8();
		
		//8.聚合查
		test9();
	}
	//普通的oid查询
	private static void test1() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Customer customer = session.get(Customer.class, 9L);
		System.out.println(customer.getCust_name());
		tr.commit();
		session.close();
	}
	
	// 全查   类似sql语句的表达式  from 持久化类
	private static void test2() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("from Customer");
		List<Customer> list = qr.list();
		for (Customer customer : list) {
			//返回的是对象
			System.out.println(customer.getCust_id()+":"+customer.getCust_name());
		}
		tr.commit();
		session.close();
	}
	//条件查，类似sql语句的表达式  from 持久化类  where 属性=? 
	private static void test3() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("from Customer where cust_name like ?");
		qr.setParameter(0, "a%");
		List<Customer> list = qr.list();
		for (Customer cu : list) {
			System.out.println(cu.getCust_name());
		}
		tr.commit();
		session.close();
	}
	// 分页查  类似sql语句的表达式  from 持久化类  where 属性=? 
	private static void test4() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("from Customer");
		//mysql:  from Customer limit 0,3;
		//sqlserver:  from Customer top 0,3;
		//开始位置
		qr.setFirstResult(0);
		//结束位置
		qr.setMaxResults(3);
		List<Customer> list = qr.list();
		for (Customer customer : list) {
			System.out.println(customer.getCust_id()+":"+customer.getCust_name());
		}
		tr.commit();
		session.close();
	}
	// 单列查  返回是Object
	private static void test5() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("select cust_id from Customer");
		List<Object> list = qr.list();
		for (Object object : list) {
			System.out.println(object);
		}
		tr.commit();
		session.close();
	}
	// 多列查 返回的是Object数组
	private static void test6() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("select cust_id,cust_name,cust_phone from Customer");
		List<Object[]> list = qr.list();
		for (Object[] objects : list) {
			System.out.println(objects[0]+"--"+objects[1]+"--"+objects[2]);
		}
		tr.commit();
		session.close();
	} 
	//投影查询
	//步骤：
	// 1 查多少字段 就需要在持久化类中写多少个构造参数
    // 2 语法的书写: select new 持久化类(要查的值1,要查的值2)  from 持久化类;
	//返回的是对象
	private static void test7() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("select new Customer(cust_id,cust_name,cust_phone) from Customer");
		List<Customer> list = qr.list();
		for (Customer customer : list) {
			System.out.println(customer.getCust_id()+"--"+customer.getCust_name()+"--"+customer.getCust_phone());
		}
		tr.commit();
		session.close();
	}
	// 排序查
	//升序：asc
	//降序：desc
	private static void test8() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("from Customer order by cust_id asc");
		List<Customer> list = qr.list();
		for (Customer customer : list) {
			System.out.println(customer.getCust_id()+"--"+customer.getCust_name()+"--"+customer.getCust_phone());
		}
		tr.commit();
		session.close();
	}
	//聚合查
	private static void test9() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("select count(*) from Customer");
		Object object = qr.uniqueResult();
		System.out.println(object);
		tr.commit();
		session.close();
	} 
	
}

between and查询

//10.between and查询
	private static void test11() {
		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("select cust_name from Customer where (cust_id between ? and  ?)");
		qr.setParameter(0, 5L);
		qr.setParameter(1, 10L);
		List<Object> list = qr.list();
		for (Object object : list) {
			System.out.println(object);
		}
		tr.commit();
		session.close();
	}

多表查询

//连表查询根据linkman的name 查找到customer的信息
	@Test
	private static void test10() {

		Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("from Customer c,Linkman l where c.cust_id = l.custmoer.cust_id and l.lkm_name = ?");
		qr.setParameter(0, "小米21");
		//得到的list是object[]，数组中的元素是customer对象和linkman对象；
		List<Object[]> list = qr.list();
		
		for (int i = 0; i < list.size(); i++) {
			Object[] object = (Object[]) list.get(i);
			//查询到的是两个持久化类的对象。把object强转为customer对象就可以使用了
			Customer customer=(Customer) object[0];
			System.out.println(customer.getCust_name());
		}
		tr.commit();
		session.close();
	}

多表查询具体信息

//根据linkman的name查询customer中的name和address
private static void test10() {
Session session = HibernateUtils.openSession();
		Transaction tr = session.beginTransaction();
		Query qr = session.createQuery("select c.cust_address,c.cust_name from Customer c,Linkman l where c.cust_id = l.custmoer.cust_id and l.lkm_name = ?");
		qr.setParameter(0, "小米21");
		//得到的list是object[]，数组中的元素是customer对象和linkman对象；
		List<Object[]> list = qr.list();
		
		for (int i = 0; i < list.size(); i++) {
			Object[] object =  list.get(i);
			System.out.println("地址："+object[0]+"\t姓名："+object[1]);
		
		}
		tr.commit();
		session.close();
	}