用另一个表中的值替换 clob 中的值

Question

我有 2 个表，在表 1 中，我有一个具有错误值的 clob 文件，我需要用另一个表中的正确值替换它。

表1

column1	column2 (clob)
1234	abc...N0001234...
2345	askdfa.. N0002434....

在上面的 table1 N000**** 不正确，现在我有 table2，其中我有正确的值（这不是 clob）

表2

Column1	column2	column3
1234	N0004567	N0001234
2345	N0002435	N0002434

现在我尝试了类似下面的抛出错误

update table1
set column2 = replace (column2, select column3 from table2 where table1.column1 = table2.column1,
                              select column2 from table2 where table1.column1 = table2.column1)

where table1.column1 in (select column1 from table2 where table1.column1 = table2.column1);

但是 oracle 抛出了一个缺少表达式的错误。

有人可以帮帮我吗？

Answer 1

您可以使用MERGE 声明：

MERGE INTO table1 dst
USING (
  SELECT t1.ROWID AS rid,
         REPLACE(t1.column2, t2.column3, t2.column2) AS replacement
  FROM   table1 t1
         INNER JOIN table2 t2
         ON (t1.column1 = t2.column1 AND t1.column2 LIKE '%'||t2.column3||'%')
) src
ON (src.rid = dst.ROWID)
WHEN MATCHED THEN
  UPDATE
  SET column2 = src.replacement;

其中，对于样本数据：

CREATE TABLE table1 (column1, column2) AS
SELECT 1234, EMPTY_CLOB() || RPAD('abc', 4000,  '.') || 'N0001234' FROM DUAL UNION ALL
SELECT 2345, TO_CLOB('askdfa.. N0002434....') FROM DUAL;

在MERGE之后，表格包含：

COLUMN1	COLUMN2
1234	abc.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................N0004567
2345	askdfa.. N0002435....

db小提琴here