Oracle：无法根据插入的最新记录获取记录并与多个表连接

Question

我有一张表格如下：

USERS

 USERID             EMAIL
 ----------------------
 1              xxx@xxx.com
 2              yyy@yyy.com

AUDIT_ITEM
 AI_ID          AI_NAME
----------------------------
   1            AAA
   2            BBB
   3            CCC
   4            DDD

AUDIT_LOG
AL_ID       USERID      AI_ID   PACKAGING_ID        INSERT_DATE
--------------------------------------------------------------------
1           2           1           100             09/09/2014
2           1           2           102             09/09/2014
3           1           3           103             09/09/2014
4           1           1           100             09/09/2014 ( LATEST RECORD INSERTED)

现在我希望用户根据AUDIT_LOG表中插入的最新记录发送电子邮件（在本例中为xxx@xxx.com），其中AI_NAME ='AAA'且PACKAGING_ID = 100.注意INSERT_DATE属于DATE类型

Answer 1

这使用with子句将日志条目限制为packaging_id 100和ai_name AAA的日志条目。然后它变成：

with logs as
       (select l.*
          from audit_log l join audit_item i on l.ai_id = i.ai_id
         where l.packaging_id = 100 and i.ai_name = 'AAA')
select u.email
  from users u join logs l on u.userid = l.userid
 where l.insert_date = (select max(insert_date) from logs);