sql - 标量子查询中的子查询失败并出现错误 ORA-00936 缺少表达式

Question

1. 这是不起作用的查询：

   SELECT distinct ord.DateOrdered
      , (SELECT docno 
         FROM th_mm_c_orderline_history 
         WHERE th_mm_c_orderline_history_id 
               in (SELECT max(th_mm_c_orderline_history_id) 
                   FROM th_mm_c_orderline_history 
                   GROUP BY c_orderline_id ) 
         order by docno,c_orderline_id) as docno 
   FROM c_order ord 
   INNER JOIN c_orderline on c_orderline.c_order_id = ord.c_order_id 
   INNER JOIN th_mm_c_orderline_history 
         on th_mm_c_orderline_history.c_order_id=ord.c_order_id
   

   它正在向我抛出ORA-00936 缺少表达式错误

2. 此查询工作正常：

   SELECT docno 
   FROM th_mm_c_orderline_history 
   WHERE th_mm_c_orderline_history_id 
         in (SELECT max(th_mm_c_orderline_history_id) 
             FROM th_mm_c_orderline_history 
             GROUP BY c_orderline_id ) 
   order by docno,c_orderline_id as docno
   

Answer 1

只需从内联选择中删除 order by 子句。你不能在那里使用 order by 子句。如果需要，您可以在外部选择中使用它...这是您可以在没有错误的情况下完成所有三个操作的方法：

SELECT distinct ord.DateOrdered
       , (SELECT docno FROM th_mm_c_orderline_history 
          WHERE th_mm_c_orderline_history_id 
                 in (SELECT max(th_mm_c_orderline_history_id) 
                     FROM th_mm_c_orderline_history 
                     GROUP BY c_orderline_id) 
          ) as docno 
FROM c_order ord 
INNER JOIN c_orderline on c_orderline.c_order_id = ord.c_order_id 
INNER JOIN th_mm_c_orderline_history on th_mm_c_orderline_history.c_order_id=ord.c_order_id

Answer 2

您可以在整个 select 语句的末尾使用“order by statement”。由于在 select 语句中没有使用 C_ORDERLINE_ID 列，因此按语句排序可能会出错。在下面试试这个版本。

 SELECT DISTINCT
       C_ORDER.DATEORDER,
       (SELECT DOCNO
          FROM TH_MM_C_ORDERLINE_HISTORY
         WHERE     C_ORDER_ID = C_ORDER_ID
               AND TH_MM_C_ORDERLINE_HISTORY_ID IN (  SELECT MAX (TH_MM_C_ORDERLINE_HISTORY_ID)
                                                        FROM TH_MM_C_ORDERLINE_HISTORY
                                                    GROUP BY C_ORDERLINE_ID)) AS DOCNO,
       C_ORDER.DOCUMENTNO
  FROM C_ORDER 
  INNER JOIN C_ORDERLINE ON C_ORDERLINE.C_ORDER_ID = C_ORDER_ID 
  ORDER BY DOCNO, C_ORDERLINE_ID;