Update Query不工作，执行时间过长

Question

我正在尝试更新table1与table2列"sc"这是我的

table1

<表类> CP tbody><<tr>刺德瑞德。sab

你能试试这个吗?

update table1 set table1.cp = source.sc
from (select * from table2 where cp <> sc ) source
where table1.cp = source.cp;
select * from table1;
+-----------+
|    CP     |
+-----------+
| stab      |
| crawl.com |
| dredal    |
| sab       |
+-----------+