Question

如果出版商是＆＃39; x＆＃39;我需要将图书的价格提高5％。其他人则为10％。我需要使用＆＃39;当前的＆＃39;并且＆＃39;回到＆＃39;子句。

DECLARE
CURSOR c1 IS SELECT book_id FROM books WHERE publisher = 'x';
CURSOR c2 IS SELECT book_id FROM books WHERE publisher != 'x';
BEGIN
UPDATE books SET price = price + 0.05 * price WHERE CURRENT OF c1;
UPDATE books SET price = price + 0.1 * price WHERE CURRENT OF c2;
END;

是否有简单的方法，而不是做两个游标和两个更新，例如＆＃39;当其他人＆＃39;？

Answer 1

简单直..

UPDATE books SET price =decode(publisher,'x'
                               ,price + 0.05 * price  -- If 'x'
                               ,price + 0.1 * price); -- else

Answer 2

为什么一件简单的事情变得更复杂？只是做：

UPDATE books SET price = price + 0.05 * price WHERE publisher = 'x';
UPDATE books SET price = price + 0.1 * price WHERE publisher != 'x'

PL / SQL更新，其中

2 个答案: