问题[nearest-neighbor](dba)

我有两个名为的表my_nodes，restaurants其中包含名称和geoloc数据。我需要为每个 my_node 返回最近的餐厅和从节点到餐厅的距离的表。

    select n.node_id, r.r_name , sdo_nn_distance(1) as min_distance from 
        (select nodeid as node_id, geoloc  from my_nodes@my_server ) n,
        (select r_name, GEOLOC from restaurants) r 
        where sdo_nn   (n.geoloc, r.GEOLOC,   'Unit = MILE sdo_num_res = 1', 1) = 'TRUE'

上面的查询返回：

    ORA-13249: SDO_NN cannot be evaluated without using index
    ORA-06512: at "MDSYS.MD", line 1723
    ORA-06512: at "MDSYS.MDERR", line 17
    ORA-06512: at "MDSYS.PRVT_IDX", line 9

如何解决？