menu模块的自关联查询

<!-- 针对菜单的父子关系，定义的树状结构ResultMap  -->
   <resultMap  id="menuResultMap"  type="com.awcloud.user.pojo.custom.MenuCustom">  
        <id column="id" property="id" jdbcType="BIGINT" />
	    <result column="name" property="name" jdbcType="VARCHAR" />
	    <result column="menu_code" property="menuCode" jdbcType="VARCHAR" />
	    <result column="parent_id" property="parentId" jdbcType="BIGINT" />
	    <result column="url" property="url" jdbcType="VARCHAR" />
	    <result column="order" property="order" jdbcType="INTEGER" />
	    <result column="type" property="type" jdbcType="INTEGER" />
	    <result column="icon" property="icon" jdbcType="VARCHAR" />
	    <result column="description" property="description" jdbcType="VARCHAR" />
	    <result column="enabled" property="enabled" jdbcType="BIT" />
          
          
        <!-- 查询子菜单 -->  
        <collection property="children" column="id" select="getChildrenMenus" />  
          
    </resultMap>  
      

       <!-- 查询特定menu的所有子菜单，返回menuResultMap -->
    <select id="getChildrenMenus" parameterType="int" resultMap="menuResultMap">  
        select * from tb_menu where parent_id = #{id}  
    </select> 
      <!-- 查询所有顶级菜单并且带子菜单集合，返回menuResultMap  -->
    <select id="getTopLevelMenusWithChildren" resultMap="menuResultMap" >  
        select * from tb_menu   where type=1 and (parent_id IS NULL or parent_id=0)
    </select>