oracle解析XML文件异常

[Kevin_Jame]

最近在学习如何用oracle自带xmltable 解析xml文件，但是发现以下问题。
ORA-00907 :缺失右括号
代码如下：

with action as
 (SELECT *
    FROM XMLTABLE('$B/GET_DESCRIPTIONOutput' PASSING XMLTYPE('<?xml version="1.0" encoding="gb2312" ?> 
<GET_DESCRIPTIONOutput >
  <P_H> <p_shipment>121212</p_shipment>
         <P_SHIP_DATA>2016-02-01</P_SHIP_DATA>
         <P_RECITE_DATA>2016-02-04</P_RECITE_DATA>
  </P_H>  
  <P_D>
   <DT>
  <item_id>520038396</item_id>
        <unit_qty>1</unit_qty> 
         </DT>
         <DT>
 <item_id>520038394</item_id>
        <unit_qty>2</unit_qty> 
         </DT>       
  </P_D> 
</GET_DESCRIPTIONOutput>
') as b COLUMNS p_shipment VARCHAR2(50) PATH
                   '/GET_DESCRIPTIONOutput/P_H/p_shipment',
                   P_SHIP_DATA VARCHAR2(50) PATH
                   '/GET_DESCRIPTIONOutput/P_H/P_SHIP_DATA',
                   P_RECITE_DATA VARCHAR2(50) PATH
                   '/GET_DESCRIPTIONOutput/P_H/P_RECITE_DATA',
                   XT_DT xmltype path 'P_D/DT'))
select s. p_shipment,
       s.P_SHIP_DATA,
     s.P_RECITE_DATA,
 xmltable('/DT/item_id' passing s.XT_DT columns item_id VARCHAR2(400) path
          'item_id',
          unit_qty VARCHAR2(400) path 'unit_qty')

  from action s;