Oracle：从自我联接更新

Question

给定此表：

MODEL   RESULT  DATE    SECTION
AABBCC  10.5    1/1/2001    1
AABBCC  15.6    1/1/2001    2
AABBCC  42.2    1/1/2001    3
AABBCC  35.4    1/1/2001    4
AABBCC  82.1    1/1/2001    5
AABBCC  95.3    1/1/2001    6
AABBCC  76.5    1/1/2001    7

我要确保对于每个部分（对于相同的日期/模型），结果始终大于或等于任何前面的部分。

例如，如果第7行的结果小于第6行的结果，则我需要将第7行设置为等于第6行的结果。

同样，如果第5行的结果小于第2行的结果，则需要将第5行的结果设置为第2行的结果。

我可以使用如下自连接找到较高部分的值比前一个部分低的情况：

SELECT 
  t1.MODEL as MODEL,
  t1.DATE as DATE
  t1.RESULT as RESULT_1,
  t1.SECTION as SECTION_1,
  t2.RESULT as RESULT_2,
  t2.SECTION as SECTION_2
FROM table t1
INNER JOIN table t2
ON t1.DATE = t2.DATE AND t1.MODEL = t2.MODEL
WHERE t2.section > t1.section AND
      t2.result < t1.result 

产生以下内容：

MODEL   DATE    SECTION_1   RESULT_1    SECTION_2   RESULT_2
AABBCC  1/1/2001    3   42.2    4   35.4
AABBCC  1/1/2001    6   95.3    7   76.5

我试图像这样合并数据：

MERGE INTO table new
USING (

SELECT 
  t1.MODEL as MODEL,
  t1.DATE as DATE
  t1.RESULT as RESULT_1,
  t1.SECTION as SECTION_1,
  t2.RESULT as RESULT_2,
  t2.SECTION as SECTION_2
FROM table t1
INNER JOIN table t2
ON t1.DATE = t2.DATE AND t1.MODEL = t2.MODEL
WHERE t2.section > t1.section AND
      t2.result < t1.result 
) old

ON (new.DATE = old.DATE AND new.section > old.section)
WHEN MATCHED THEN
UPDATE
SET new.result = old.result;

但我收到以下错误：

错误报告-SQL错误：ORA-30926：无法在源表30926中获得稳定的行集。00000-“无法在源表中获得稳定的行集” *原因：无法获得稳定的行集由于dml活动较大或不确定的where子句而被获取。 *操作：删除所有不确定的where子句，然后重新发出dml。

Answer 1

MERGE INTO table new
USING (
SELECT  MODEL,
        DATE,
        RESULT,
        SECTION
FROM (
SELECT 
  t1.MODEL as MODEL,
  t1.DATE as DATE,
  MAX(t1.RESULT) OVER (PARTITION BY t1.MODEL ORDER BY t1.SECTION) as RESULT,
  t1.SECTION as SECTION,
  t1.RESULT as OLD_RESULT
FROM table t1)
WHERE OLD_RESULT != RESULT
) old
ON (new.DATE = old.DATE AND new.section = old.section and new.MODEL = old.MODEL )
WHEN MATCHED THEN
UPDATE
SET new.result = old.result;