hql语法002

1、

package cn.jbit.hibernatedemo.test;

import java.util.Iterator;
import java.util.List;

import org.hibernate.*;
import org.junit.Test;

import cn.jbit.hibernatedemo.dao.HibernateUtil; import cn.jbit.hibernatedemo.entity.DeptSalary; public class Eg { /** * 统计部门个数。 */ @Test public void egDept() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Long count = (Long) session.createQuery( "select count(*) from Dept d").uniqueResult(); System.out.println(count); } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计员工工资。 */ @Test public void egEmp() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Double salarySum = (Double) session.createQuery( "select sum(e.salary) from Emp e").uniqueResult(); System.out.println(salarySum); } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计员工最低工资。 */ @Test public void egEmpMinSalary() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Double salary = (Double) session.createQuery( "select min(e.salary) from Emp e").uniqueResult(); System.out.println(salary); } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计员工最高工资。 */ @Test public void egEmpMaxSalary() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Double salary = (Double) session.createQuery( "select max(e.salary) from Emp e").uniqueResult(); System.out.println(salary); } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计员工平均工资。 */ @Test public void egEmpAvgSalary() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Double salary = (Double) session.createQuery( "select avg(e.salary) from Emp e").uniqueResult(); System.out.println(salary); } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计最低工资、最高工资以及平均工资。 */ @Test public void egEmpSalary() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Object[] salarys = (Object[]) session.createQuery( "select min(salary),max(salary),avg(salary) from Emp") .uniqueResult(); System.out .println(salarys[0] + "," + salarys[1] + "," + salarys[2]); } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计员工职位个数。 */ @Test public void egJobEmp() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Object count = session.createQuery( "select count(distinct job) from Emp ").uniqueResult(); System.out.println(count.getClass().getName()); } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 按职位统计员工个数。 */ @Test public void eg1() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); List<Object[]> list = session.createQuery( "select job,count(e) from Emp e group by job").list(); for (Object[] obj : list) System.out.println(obj[0] + "," + obj[1]); } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计各个部门的平均工资 */ @Test public void eg2() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Iterator<Object[]> it = session .createQuery( "select e.dept.deptName,avg(e.salary) from Emp e group by e.dept.deptName") .list().iterator(); Object[] obj = null; while (it.hasNext()) { obj = it.next(); System.out.println(obj[0] + "," + obj[1]); } } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计各个职位的最低工资和最高工资 */ @Test public void eg3() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Iterator<Object[]> it = session .createQuery( "select job,min(salary),max(salary) from Emp group by job") .list().iterator(); Object[] obj = null; while (it.hasNext()) { obj = it.next(); System.out.println(obj[0] + "," + obj[1] + "," + obj[2]); } } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计各个部门平均工资高于4000元的部门名称，打印部门名称、部门平均工资 */ @Test public void eg4() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Iterator<Object[]> it = session .createQuery( "select e.dept.deptName,avg(e.salary) from Emp " + "e group by e.dept.deptName having avg(e.salary)>4000") .list().iterator(); Object[] obj = null; while (it.hasNext()) { obj = it.next(); System.out.println(obj[0] + "," + obj[1]); } } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } /** * 统计各个部门平均工资高于4000元的部门名称，打印部门名称、部门平均工资，使用JavaBean封装查询结果 */ @Test public void eg4JavaBean() { Session session = null; try { // 获取session session = HibernateUtil.currentSession(); Iterator<DeptSalary> it = session .createQuery( "select new cn.jbit.hibernatedemo.entity.DeptSalary(e.dept.deptName,avg(e.salary))" + " from Emp e group by e.dept.deptName having avg(e.salary)>4000") .list().iterator(); DeptSalary deptSalary = null; while (it.hasNext()) { deptSalary = it.next(); System.out.println(deptSalary.getDeptName() + "," + deptSalary.getAvgSalary()); } } catch (Exception e) { e.printStackTrace(); } finally { // 关闭session  HibernateUtil.closeSession(); } } }