一对多、多对多（注解）

 1.一对多用户和账户     @Select("select * from user")     @Results(id = "resultMap",value = {             @Result(id = true,property = "userId",column ="id"),             @Result(property = "userName",column ="username"),             @Result(property = "userSex",column ="sex"),             @Result(property = "userAddress",column ="address"),             @Result(property = "accounts",column ="id",many=@Many(select = "com.itheima.dao.IAccountDao.getAccountById",                     fetchType = FetchType.LAZY)),     })     List<User> findAll();      2.多对多   是由多个一对多组成，但是会产生中间表，上面的步骤相同，查询需要用到内连接   	@Select("SELECT * FROM role WHERE id IN(SELECT rid FROM user_role WHERE uid=#{id}) ")     Role getRoleById(Integer id);

文章来源: https://blog.csdn.net/qq1424035130/article/details/91446327