在Oracle中交换列值

问题描述：

我正在解决一个难题，并遇到了使用DML查询交换列值的问题:

I was solving one of the puzzles and came across swapping column values using DML queries:

SELECT * FROM TEMP_TABLE;
ID1, ID2
--------
20, 15
20, 15
20, 15

解决方案是数学计算:

UPDATE TEMP_TABLE SET ID1=ID1+ID2;
UPDATE TEMP_TABLE SET ID2=ID1-ID2;
UPDATE TEMP_TABLE SET ID1=ID1-ID2;

现在，我正在尝试确定是否可以将其应用于字符串.

Now, I am trying to figure out whether this can be applied to Strings or not, please suggest.

SELECT * FROM TEMP_TABLE_NEW;
ID1, ID2
--------
ABC, XYZ
ABC, XYZ
ABC, XYZ

答

不需要三个更新语句，一个就足够了:

There's no need to have three update statements, one is sufficient:

UPDATE temp_table_new 
SET    id1 = id2, 
       id2 = id1;