二十五、 “我的消息”中MyBatis的left join左连查询（mapper，modal， implement）

MyBatis的left join左连查询2张表的数据

1. 在implement中的SysAnnouncementSendMapper调用方法：

getMyAnnouncementSendList（）和getOne（）

@Service
public class SysAnnouncementSendServiceImpl 
extends ServiceImpl<SysAnnouncementSendMapper, SysAnnouncementSend>
 implements ISysAnnouncementSendService
 {

    @Resource
    private SysAnnouncementSendMapper sysAnnouncementSendMapper;

    
    @Override
    public Page<AnnouncementSendModel> getMyAnnouncementSendPage(
Page<AnnouncementSendModel> page,
AnnouncementSendModel announcementSendModel)
 {
        return page.setRecords(sysAnnouncementSendMapper.getMyAnnouncementSendList(page, announcementSendModel));
}

    @Override
    public AnnouncementSendModel getOne(String sendId) 
{
       return sysAnnouncementSendMapper.getOne(sendId);

    }

（2）定义：SysAnnouncementSendMapp