Mapper多表关联查询学习 _多表关联

青春须早为，岂能长少年。这篇文章主要讲述Mapper多表关联查询学习相关的知识，希望能为你提供帮助。
1、首先写sql语句

select p.id, p.create_time, p.update_time, p.create_user, p.update_user, p.project_name, p.test_user, p.dev_user, p.simple_desc, p.other_desc, p.project_code, p.belong_env_id, p.status_id,u.status_name,u.description from projectinfo_temp p LEFT JOIN usestatus u on p.status_id = u.id

2、关联pojo

@ToString public class ProjectinfoTemp {private Integer id; private Date createTime; private Date updateTime; private String createUser; private String updateUser; private String projectName; private String testUser; private String devUser; private String simpleDesc; private String otherDesc; private String projectCode; private Integer belongEnvId; private Integer statusId; /** *关联状态表激活状态 */ private Usestatus usestatus;

状态表

/** * * @author liwen406 * @date 2019-04-21 09:12 */ @ToString public class Usestatus { private Integer id; private String statusName; private String description;

3编写关联sql语句

模仿写法

& lt; sql id="WithBase_Column_List" & gt; p.id, p.create_time, p.update_time, p.create_user, p.update_user, p.project_name, p.test_user, p.dev_user, p.simple_desc, p.other_desc, p.project_code, p.belong_env_id, p.status_id,u.status_name,u.description & lt; /sql& gt;

< select id="selectByExample" resultMap="BaseResultMap" parameterType="com.apitest.pojo.ProjectinfoTempExample" > select < if test="distinct" > distinct < /if> < include refid="Base_Column_List" /> from projectinfo_temp < if test="_parameter != null" > < include refid="Example_Where_Clause" /> < /if> < if test="orderByClause != null" > order by ${orderByClause} < /if> < /select> < select id="selectByExamplestart" resultMap="WithBaseResultMap"> select < if test="distinct" > distinct < /if> < include refid="WithBase_Column_List" /> from projectinfo_temp p LEFT JOIN usestatus u on p.status_id = u.id < if test="_parameter != null" > < include refid="Example_Where_Clause" /> < /if> < if test="orderByClause != null" > order by ${orderByClause} < /if> < /select>

4前端调用写法

< div class="x_content"> < table id="datatable" class="table table-striped table-bordered"> < thead> < tr> < th class="table-title"> 应用编号< /th> < th class="table-title"> 应用名称< /th> < th class="table-title"> 测试负责人< /th> < th class="table-title"> 开发负责人< /th> < th class="table-title"> 模块/接口/用例< /th> < th class="table-title"> 状态< /th> < th class="table-title"> 操作< /th> < /tr> < /thead> < tbody> < tr th:each="pagefo:${pageInfo.list}"> < td th:text="${pagefo.projectCode}"> < /td> < td th:text="${pagefo.projectName}"> < /td> < td th:text="${pagefo.testUser}"> < /td> < td th:text="${pagefo.devUser}"> < /td> < td th:text="${pagefo.belongEnvId}"> < /td> < td th:text="${pagefo.usestatus.statusName}"> < /td> < td> < a type="button" class="fa fa-bug btnbtn-round btn-success" th:href="https://www.songbingjia.com/android/@{/run/}+${pagefo.projectCode}"> 运行< /a> < a type="button" class="fa fa-edit btn btn-round btn-info" th:href="https://www.songbingjia.com/android/@{/cache/editProjectInf/}+${pagefo.projectCode}"> 编辑< /a> < a type="button" class="fa fa-trash-o btnbtn-round btn-danger" th:href="https://www.songbingjia.com/android/@{/deleteProjectinfoTemp/}+${pagefo.projectCode}"> 删除< /a> < /td> < /tr> < /tbody> < /table> < div class="box-footer"> < div class="pull-left"> < div class="form-group form-inline"> < span th:text="‘共‘+${pageInfo.getPages()}+‘页‘"> < /span> , < span th:text="‘当前为‘+${pageInfo.getPageNum()}+‘页‘"> < /span> < span th:text="‘总‘+${pageInfo.getTotal()}+‘条记录‘"> < /span> < /div> < /div> < div class="box-tools pull-right"> < ul class="pagination"> < li> < a th:href="https://www.songbingjia.com/android/@{/cache/project_list_cache(start=0)}" aria-label="Previous"> [首页]< /a> < /li> < li> < a th:href="https://www.songbingjia.com/android/@{/cache/project_list_cache(start=${pageInfo.pageNum-1})}"> [上一页]< /a> < /li> < li> < a th:href="https://www.songbingjia.com/android/@{/cache/project_list_cache(start=${pageInfo.pageNum+1})}"> [下一页]< /a> < /li> < li> < a th:href="https://www.songbingjia.com/android/@{/cache/project_list_cache(start=${pageInfo.pages})}" aria-label="Next"> [尾页]< /a> < /li> < /ul> < /div> < /div> < /div>

5、访问结果显示