mybatis两种嵌套查询方式
1,推荐用第一种
<select id="getTeacher2" resultMap="TeacherStudent">
select s.id sid,s.name sname,t.id tid,t.name tname
from teacher t,student s
where s.tid=tid and tid=#{tid}
</select>
<resultMap id="TeacherStudent" type="Teacher">
<result property="id" column="tid"/>
<result property="name" column="tname"/>
<collection property="students" ofType="Student">
<result property="id" column="sid"/>
<result property="name" column="sname"/>
<result property="tid" column="tid"/>
</collection>
</resultMap>
2,
<select id="getTeacher2" resultMap="TeacherStudent">
select * from mybatis.teacher where id = #{id}
</select>
<resultMap id="TeacherStudent" type="Teacher">
<collection property="students" javaType="ArrayList" ofType="Student" select="getStudentByTeacherId" column="id"/>
</resultMap>
<select id="getStudentByTeacherId" resultType="Student">
select * from mybatis.student where tid = #{tid}
</select>