<mapper namespace="com.dao.EmployeeDao">

    <insert id="insert">

        <selectKey order="BEFORE" keyColumn="employeeId,employeeGender" keyProperty="employeeId,employeeGender" resultType="com.entity.Employee">

            select employee_id employeeId,employee_gender employeeGender from employee where employee_id=13

        </selectKey>

        insert into subtable(employee_id,employee_name,employee_gender) values (#{employeeId},"mdzz",#{employeeGender})

    </insert>

</mapper>

public interface EmployeeDao {

    int insert(Employee employee);

}

@Test

    public void testInsert() {

        Employee employee = new Employee();

        EmployeeDao employeeDao = MapperFactory.generateMapper(EmployeeDao.class);

        employeeDao.insert(employee);

        System.out.println(employee);

    }

employee | CREATE TABLE `employee` (

  `employee_id` int(11) NOT NULL AUTO_INCREMENT,

  `employee_name` char(30) DEFAULT NULL,

  `employee_gender` binary(1) DEFAULT NULL,

  `employee_salary` decimal(10,2) DEFAULT NULL,

  `dept_id` int(11) DEFAULT NULL,

  PRIMARY KEY (`employee_id`)

) ENGINE=InnoDB AUTO_INCREMENT=24 DEFAULT CHARSET=utf8mb4 |