加入Oracle性能的更新语句

Question

在性能方面哪个更好？

UPDATE 
(SELECT table1.value as OLD, table2.CODE as NEW
 FROM table1
 INNER JOIN table2
 ON table1.value = table2.DESC
 WHERE table1.UPDATETYPE='blah'
) t
SET t.OLD = t.NEW;


UPDATE table1 
SET t.value = 
(SELECT CODE
 FROM table2
 WHERE table1.value = table2.DESC
) t
WHERE t.UPDATETYPE='blah';

我在这里查看原始任务的答案：Update statement with inner join on Oracle