1:返回数据。 返回为map类型的,其sql查询出来的字段,即为map中的返回字段,map中通过键值对的方式存取这些数据,其key就是sql中所查询的字段,当然,这里需要注意的一点就是,如果此字段为空,那么就不会返回此字段,记住,是不会返回,也就是说在map中的key并不存在这个字段,这个和返回实体类有一点区别,实体类中就算...
* 查询每个部门的平均薪资(返回Map) * sql: SELECT departmentId,AVG(salary) AS avg_salary FROM t_employee GROUP BY department_id;*/@TestpublicvoidselectByQueryWrapper10ReturnMap(){ QueryWrapper<Employee> queryWrapper=newQueryWrapper();//QueryWrapper<Employee> queryWrapper2=Wrappers.<Employee>query();qu...
* 查询每个部门的平均薪资(返回Map) * sql: SELECT departmentId,AVG(salary) AS avg_salary FROM t_employee GROUP BY department_id; */ @Test public void selectByQueryWrapper10ReturnMap(){ QueryWrapper<Employee> queryWrapper=new QueryWrapper(); // QueryWrapper<Employee> queryWrapper2=Wrappers.<Employee...
* 查询每个部门的平均薪资(返回Map) * sql: SELECT departmentId,AVG(salary) AS avg_salary FROM t_employee GROUP BY department_id; */ @Test public void selectByQueryWrapper10ReturnMap(){ QueryWrapper<Employee> queryWrapper=new QueryWrapper(); // QueryWrapper<Employee> queryWrapper2=Wrappers.<Employee...