Update/Merge a table 在 oracle 中使用子查询

Question

我有以下 table - 帐户详细信息

 Account_No   Request_Id   Issue_date    Amount   Details
   1              567       20150607      6     Loan
   2              789       20170406      5     Personal
   3                        20170216      7     
   3              987       20160525      5     Loan
   3              456       20170112      6     Loan
   4              234       20171118      7     Loan

我必须使用以下逻辑更新帐户的请求 ID 为空或详细信息为空的 request_id。需要根据发布日期获取帐户的最新请求 ID，并且必须更新请求 ID（最新请求 ID + 1），其中 request_id 为空或详细信息为空。所以结果应该是

 Account No   Request_Id   Issue_date    Amount   Details
   1              567       20150607      6     Loan
   2              789       20170406      5     Personal
   3              457       20170216      7     
   3              987       20160525      5     Loan
   3              456       20170112      6     Loan
   4              234       20171118      7     Loan

我尝试了以下查询

MERGE INTO AccountDetails a
USING ( select Request_Id + 1,ROW_NUMBER() OVER (PARTITION BY B.Account_No 
ORDER BY B.Issue_date desc) AS RANK_NO 
          from AccountDetails ) b
ON ( a.Account_No = b.Account_No AND a.DETAILS IS  NULL)
WHEN MATCHED THEN 
UPDATE SET  a.Request_Id = b.Request_Id
WHERE B.RANK_NO = 1;

Answer 1

update accountdetails set request_id=(select max(request_id)+1 from accountdetails) 
   where request_id is null and details is null;

Answer 2

听起来您需要使用解析 LAG 函数来确定上一行的 request_id，例如：

MERGE INTO account_details tgt
  USING (SELECT account_no,
                CASE WHEN request_id IS NULL THEN 1 + LAG(request_id) OVER (PARTITION BY account_no ORDER BY issue_date)
                     ELSE request_id
                END request_id,
                issue_date,
                amount,
                DETAILS,
                ROWID r_id
         FROM   accountdetails) src
    ON (tgt.rowid = src.r_id)
WHEN MATCHED THEN
  UPDATE SET tgt.request_id = src.request_id;

当然，这个设计看起来有点奇怪 - 为什么 request_id 首先是 null？它是一个独特的专栏吗？如果是这样，如果您最终用替换 ID 复制现有的 request_id 会怎样？此外，如果它是空帐号的第一行 request_id?

，应该会发生什么

Update/Merge a table 在 oracle 中使用子查询

Update/Merge a table using sub query in oracle

oracle

oracle10g

oracle11g