QueryDSL 3.4.3 使用子查询

因为时间有限先记录一下简单的几个写法，今天在项目中尝试一下，后续补充。

需要了解更多详细信息可以到官网查看：http://www.querydsl.com/static/querydsl/3.4.3/reference/html_single/#d0e593

主要疑惑的是子查询先记录一下：

example：

QDepartment department = QDepartment.department;
QDepartment d = new QDepartment("d");
query.from(department)
    .where(department.employees.size().eq(
        new JPASubQuery().from(d).unique(d.employees.size().max())
     )).list(department);

QEmployee employee = QEmployee.employee;
QEmployee e = new QEmployee("e");
query.from(employee)
    .where(employee.weeklyhours.gt(
        new JPASubQuery().from(employee.department.employees, e)
        .where(e.manager.eq(employee.manager))
        .unique(e.weeklyhours.avg())
    )).list(employee);