第一种：查询多次，查询部门的时候会根据部门的编号去查询部门下的高基表 n+1
<resultMap id="ClassifyVOResultMap" type="com.ly.business.entity.highbasetable.ClassifyVO">
<id column="GJBBH" jdbcType="VARCHAR" property="link" />
<result column="GJBMC" jdbcType="VARCHAR" property="title" />
</resultMap>
<resultMap id="DeptVOResultMap" type="com.ly.business.entity.highbasetable.ClassifyVO">
<id column="BMBH" jdbcType="VARCHAR" property="link" />
<result column="BMMC" jdbcType="VARCHAR" property="title" />
<collection property="children" column="BMBH" javaType="ArrayList" ofType="com.ly.business.entity.highbasetable.ClassifyVO"
select="selectDeptClassify">
</collection>
</resultMap>
<!-- 查询部门信息 -->
<select id="selectDeptAll" resultMap="DeptVOResultMap">
SELECT T.BMBH,T.BMMC FROM (SELECT BMBH,BMMC FROM LY_XTGL_BMXXB WHERE FBMBH ='000') T
</select>
<!-- 查询部门下的高基表信息 -->
<select id="selectDeptClassify" resultMap="ClassifyVOResultMap" parameterType="java.lang.String">
SELECT T.BMBH,T.BMMC,T2.GJBBH,T2.GJBMC FROM
(SELECT BMBH,BMMC FROM LY_XTGL_BMXXB WHERE FBMBH ='000') T LEFT JOIN LY_GJBB_GJBBMZJB T1 ON T.BMBH=T1.BMBH
LEFT JOIN LY_GJBB_GJBXX T2 ON T1.GJBBH = T2.GJBBH
WHERE T.BMBH = #{BMBH} ORDER BY T.BMBH
</select>
第二种：查询一次
<resultMap id="DeptVOResultMap" type="com.ly.business.entity.highbasetable.ClassifyVO">
<id column="BMBH" jdbcType="VARCHAR" property="link" />
<result column="BMMC" jdbcType="VARCHAR" property="title" />
<collection property="children" javaType="ArrayList" ofType="com.ly.business.entity.highbasetable.ClassifyVO">
<id column="GJBBH" jdbcType="VARCHAR" property="link" />
<result column="GJBMC" jdbcType="VARCHAR" property="title" />
</collection>
</resultMap>
<!-- 查询部门分类下高基表信息 -->
<select id="selectDeptClassify" resultMap="DeptVOResultMap" parameterType="java.lang.String">
SELECT T.BMBH,T.BMMC,T2.GJBBH,T2.GJBMC FROM
(SELECT BMBH,BMMC FROM LY_XTGL_BMXXB WHERE FBMBH ='000') T LEFT JOIN LY_GJBB_GJBBMZJB T1 ON T.BMBH=T1.BMBH
LEFT JOIN LY_GJBB_GJBXX T2 ON T1.GJBBH = T2.GJBBH
ORDER BY T.BMBH
</select>