Mapper接口如下：

• 例1

@Select("SELECT t_question.*,t_student.`name` FROM t_question,t_student WHERE t_question.student_id=t_student.id") List getQuestionStudent(Pagination page);

• 例2

  @Select("SELECT a.id,a.name,a.age,b.describe FROM USER a LEFT JOIN userinfo b ON a.id = b.user_id where a.id=#{id}")

其实复杂业务逻辑sql还是推荐用xml，更方便些