尝试合并时合并条件在 oracle 中不起作用

Question

我有一张桌子：

--------------
|id   descrip |
|1  A         |
|2  B         |
|3  C         |
|3  D         |
|3  E         |
|4  F         |
|4  F         |

我的预期输出是：

--------------
|id descrip |
|1  A       |
|2  B       |
|3C C       |
|3D D       |
|3E E       |
|4  F       |
|4  F       |

我尝试使用第一种方法：

merge into rules_table a
using rules_table b
on (a.id = b.id and a.descrip and a.rowid > b.rowid)
when matched then
  update set a.id = b.id || b.descrip

我尝试的第二种方法是：

update rules_table a
   set a.id =
       (select b.id || b.descrip
          from rules_table b
         where b.id = a.id
           and b.descrip = a.descrip
           and a.rowid = b.rowid)

但是，我没有得到想要的输出。

Answer 1

根据您的预期结果，我认为您正在寻找以下内容：

MERGE INTO rules_table a
USING (SELECT rowid, id, descrip, COUNT(DISTINCT descrip) over (PARTITION BY id) cnt
         FROM rules_table) b
 ON (a.rowid = b.rowid AND b.cnt > 1)
 WHEN MATCHED THEN UPDATE 
  SET a.id=b.id||b.descrip

以下也应该有效：

UPDATE rules_table
   SET id = id||descrip
 WHERE id IN (SELECT id
                FROM rules_table
               GROUP BY id
              HAVING COUNT(DISTINCT descrip) > 1)