Question

我有以下SELECT：

(SELECT DISTINCT
   V1.FORPDM_ID AS HVID,
   1 AS IMPORT_STATUS,
   V1.CREATEDAT AS IMPORT_DATE,
   'ok' AS IMPORT_MESSAGE,
   V1.ID AS AT_ID,
   V1.FORPDM_TRANSACTION_ID AS TRANSACTION_ID
 FROM V_VALIDATIONCARRIER V1, V_FORPDM_DAVE_HWDEMAND V2
 WHERE
   V1.FORPDM_ID = V2.HVID AND -- JOIN CONDITION
   ...other conditions...
)

UNION ALL

(SELECT DISTINCT
   V1.FORPDM_ID AS HVID,
   0 AS IMPORT_STATUS,
   V1.CREATEDAT AS IMPORT_DATE,
   'PC_ID is null or not in V_PLANNINGCATEGORY' AS IMPORT_MESSAGE,
   V1.ID AS AT_ID,
   V1.FORPDM_TRANSACTION_ID AS TRANSACTION_ID
 FROM V_VALIDATIONCARRIER V1, V_FORPDM_DAVE_HWDEMAND V2
 WHERE (V1.FORPDM_ID = V2.HVID) AND -- JOIN CONDITION
     ...some error conditions...
)

UNION ALL

(SELECT DISTINCT
   V1.FORPDM_ID AS HVID,
   0 AS IMPORT_STATUS,
   V1.CREATEDAT AS IMPORT_DATE,
   'BAUPHASE is null or not in V_SPEEDSPECIFICMASTERDATA' AS IMPORT_MESSAGE,
   V1.ID AS AT_ID,
   V1.FORPDM_TRANSACTION_ID AS TRANSACTION_ID
 FROM V_VALIDATIONCARRIER V1, V_FORPDM_DAVE_HWDEMAND V2
 WHERE (V1.FORPDM_ID = V2.HVID) AND -- JOIN CONDITION
       ...some other error conditions...
)

在我的数据库中，有些行可以匹配错误条件，并且我想在发生这种情况时连接两个IMPORT_MESSAGE，这样我就不会得到两行HVID和两个不同的IMPORT_MESSAGE 当我在查询中使用UNION时，有没有办法在Oracle中实现这一点？

修改
经过一些测试，它起作用了。只需澄清一点：要将我的所有数据和添加到我应该选择的消息中，如下所示：

SELECT DISTINCT HVID, IMPORT_STATUS, IMPORT_DATE, TRANSACTION_ID, AT_ID, LISTAGG(IMPORT_MESSAGE, ',') 
   WITHIN GROUP (ORDER BY IMPORT_MESSAGE) AS 
      IMPORT_MESSAGE FROM ( ...my union all select... ) MYUNION 
   GROUP BY HVID, IMPORT_STATUS, IMPORT_DATE, TRANSACTION_ID, AT_ID;

Answer 1

我认为您必须在Oracle环境中使用LISTAGG函数。

例如（见：http://www.sqlines.com/mysql/functions/group_concat）：

SELECT LISTAGG(IMPORT_MESSAGE, ',') WITHIN GROUP (ORDER BY NULL)
FROM (
    .... your union all select
     ) as YOURUNION
GROUP BY YOURUNION.IMPORT_MESSAGE;

我没有Oracle数据库，所以你必须尝试。

在SQL中使用UNION时如何连接相同ID的字符串字段？

1 个答案: