mybatis 关联查询

<resultMap type="com.uban.mybatis.bean.Employee" id="MyDifEmp">
 		<id column="id" property="id"/>
 		<result column="name" property="name"/>
 		<result column="gender" property="gender"/>
 		<result column="email" property="email"/>
 		<result column="d_id" property="dept.id"/>
 		<result column="departName" property="dept.departName"/>
 	</resultMap>
 	

        //多方查一方
 	<resultMap type="com.uban.mybatis.bean.Employee" id="MyDifEmp2">
 		<id column="id" property="id"/>
 		<result column="name" property="name"/>
 		<result column="gender" property="gender"/>
 		<result column="email" property="email"/>
 		<association property="dept" javaType="com.uban.mybatis.bean.Department">
 			<id column="d_id" property="id"/>
 			<result column="departName" property="departName"/>
 		</association>
 	</resultMap>
 	
	<!--  public Employee getEmpAndDept(Integer id);-->
	<select id="getEmpAndDept" resultMap="MyDifEmp2">
		SELECT e.id ,e.name ,e.gender ,e.d_id ,e.email,
		d.id ,d.departName  FROM employee e,department d
		WHERE e.d_id=d.id AND e.id=#{id}
	</select>

//一方查多方

<resultMap type="com.uban.mybatis.bean.Department" id="myDept">
 		<id column="id" property="id"/>
 		<result column="departName" property="departName"/>
 		<collection property="emps" ofType="com.uban.mybatis.bean.Employee">
 			<id column="id" property="id"/>
 			<result column="name" property="name"/>
 			<result column="gender" property="gender"/>
 			<result column="email" property="email"/>
 		</collection>
 	</resultMap>
 	<select id="getDeptByIdPlus" resultMap="myDept">
 	
 		select d.id,d.departName,e.id,e.name,e.gender,e.email ,e.d_id
 		from department d 
 		left join employee e 
 		on d.id=e.d_id 
 		where d.id=#{id}
 	</select>

分段 查询

<select id="getEmpsByDept" resultType="com.uban.mybatis.bean.Employee">
		select * from employee where d_id=#{id}
	</select>

<resultMap type="com.uban.mybatis.bean.Department" id="MyDeptStep">
 		<id column="id" property="id"/>
 		<result column="departName" property="departName"/>
 		<collection property="emps" select="com.uban.mybatis.dao.EmployeeMapperPlus.getEmpsByDept"
 		column="id">
 			
 		</collection>
 	</resultMap>
 	<select id="getDeptByIdStep" resultMap="MyDeptStep">
 		select id,departName from department where id=#{id}
 	</select>