一对多查询

 

 

 

 

//嵌套查询

<resultMap id="specialListID2" type="com.pojo.Special">
        <id property="specialId" column="specialId"/>
        <result property="specialName" column="specialName"/>
        <result property="specialUrl" column="specialUrl"/>
        <collection property="specialCourseList" column="{specialId=specialId}" select="selectSpecialCourseList"
                    ofType="com.pojo.SpecialCourse"/>
    </resultMap>

<select id="selectSpecialCourseList" resultType="com.pojo.SpecialCourse">
        select * from specialcourse where specialId = #{specialId}
    </select>

 <select id="selectMapList" parameterType="map" resultMap="specialListID2">
        select * from special s
    </select>

 

 //结果嵌套

<resultMap id="specialListID" type="com.pojo.Special">
        <id property="specialId" column="specialId"/>
        <result property="specialName" column="specialName"/>
        <result property="specialUrl" column="specialUrl"/>
        <collection property="specialCourseList" ofType="com.pojo.SpecialCourse">
            <id property="specialCourseId" column="specialCourseId"/>
            <result property="specialId" column="specialId"/>
            <result property="courseInfoId" column="courseInfoId"/>
            <result property="sort" column="sort"/>
        </collection>
    </resultMap>

<select id="selectMapList" parameterType="map" resultMap="specialListID2">
        select * from special s
        left join specialcourse sc on sc.specialId = s.specialId
    </select>