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 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);

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