oracle更新比较Varchar [英] oracle Update comparing Varchar

问题描述

我有两个表:

OrdHead: Order_no, CustOrd
OrdItem: Item, Order_no, CustOrd

两个表都使用字母数字的Order_No联接..我需要使用Order_no在OrdHead表中使用相同的CustOrd号更新OrdItem的CustOrd(NUMBER)列.

Both the tables are joined using Order_No which is Alphanumeric.. I need to to update CustOrd (NUMBER) column of OrdItem with the same CustOrd number in OrdHead table using Order_no.

做到这一点的最佳方法是什么?我要在表中添加索引吗?

What is the best way to do that ? Do I add any index to the tables?

目前，我使用以下查询来执行此操作，但是它仅花费100,000条记录就花费了很多时间.

Currently I do it with the following query, but its taking alot of time just with 100,000 records.

UPDATE ORDITEM A SET CUSTORD =
(SELECT CUSTORD FROM ORDHEAD b WHERE b.ORDER_NO = a.ORDER_NO);

推荐答案

如果查询有效，则可以使用索引来修复性能:

If your query works, then you can fix the performance with an index:

create index idx_ordhead_order_no_custord on orderhead(order_no, custord);

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