Oracle pl/sql按问题的查询顺序,带distinct

您需要修改查询,如下所示:

SELECT DISTINCT c.CN as ClaimNumber, 
         a.ItemDate as BillReceivedDate, c.DTN as
 DocTrackNumber, a.DateStored
         FROM ItemData a,
         ItemDataPage b,
         KeyGroupData c
         WHERE a.ItemTypeNum in (112, 113, 116, 172, 189)
         AND a.ItemNum = b.ItemNum
         AND b.ItemNum = c.ItemNum
         ORDER BY a.DateStored DESC;

当执行distinct时,您的order by必须是所选列之一。

但是,在SQL Plus中执行给了我一个更有用的答案。所存储的日期需要在select语句中,这样才能工作:

    SELECT DISTINCT c.CN as ClaimNumber,          
a.ItemDate as BillReceivedDate, 
c.DTN as DocTrackNumber, 
a.DateStored         
FROM ItemData a,         
ItemDataPage b,         
KeyGroupData c         
WHERE a.ItemTypeNum in (112, 113, 116, 172, 189)         
AND a.ItemNum = b.ItemNum         
AND b.ItemNum = c.ItemNum         
ORDER BY a.DateStored DESC;

我相信ORDERBY子句的元素也必须在SELECT子句中。