<!-- <resultMap type="employee" id="emplist">
<id property="ids" column="IDS"/>
<result property="ename" column="ENAME"/>
<result property="esex" column="ESEX"/>
<result property="birthday" column="BIRTHDAY"/>
<result property="address" column="ADDRESS"/>
<result property="dept.id" column="ID"/>
<result property="dept.dname" column="DNAME"/>
<result property="dept.createtime" column="CREATETIME"/>
</resultMap> -->
这个是级联查询 一次性把两个表的内容都累出来
<!--<resultMap type="employee" id="emplist">
<id property="ids" column="IDS"/>
<result property="ename" column="ENAME"/>
<result property="esex" column="ESEX"/>
<result property="birthday" column="BIRTHDAY"/>
<result property="address" column="ADDRESS"/>
<association property="dept" resultMap="deptlist"></association>
</resultMap>
<resultMap type="dept" id="deptlist">
<result property="id" column="ID"/>
<result property="dname" column="DNAME"/>
<result property="createtime" column="CREATETIME"/>
</resultMap> -->
<!-- <resultMap type="employee" id="emplists">
<association property="dept" column="deptid" select="mapper.DeptMapper.selectDept"></association>
</resultMap>
<select id="selectAllEmployee" resultMap="emplists" >
SELECT * FROM EMPLOYEE E JOIN DEPT D ON E.DEPTID=D.ID
</select> -->
<resultMap type="employee" id="myemp">
<id column="ids" property="ids"/>
<result column="ename" property="ename" />
<result column="esex" property="esex" />
<result column="birthday" property="birthday"/>
<result column="address" property="address"/>
<association property="dept" column="deptid" select="mapper.DeptMapper.selectDept"></association>
</resultMap>
<select id="selectEmployee" resultMap="myemp">
select * from employee e where e.ids=#{id}
</select>
这两个都是分布查询 多对一也是这样的 只是association 换成collection
<resultMap type="dept" id="mydept">
<id property="id" column="id"/>
<result property="dname" column="dname"/>
<result property="createtime" column="createtime"/>
<collection property="list" column="id" select="mapper.EmployeeMapper.selectOneEmployee"></collection>
</resultMap>
<select id="selectOneDept" parameterType="Integer" resultMap="mydept">
select * from dept d where d.id=#{id}
</select>
多对一查询
联合查询一般用分布查询 resultmap标签中 type类型就是想要查询的类型 id随便写 是resultmap的唯一标识，collection标签中 property 属性指定的是联合查询的是哪个 column传入的指定的值 工select查询
resultmap 是制定封装规则 所以定义哪个对象的封装规则 那么 这个标签的type属性就写哪个
原文：http://www.cnblogs.com/gaofangquan/p/7571751.html