Question

我目前有以下三个表格：

表1

book_id    margin
-------------------
   b1       10
   b2       20
   b3       30

表2

t2_id   book_id     author_id
-----------------------------
  1         b1        100
  2         b2        200
  3         b3        300

表3

author_id    revenue
----------------------
   100          0
   200          0
   300          0

我试图用表1的对应书作者（表3）的保证金的50％更新表3的收入。结果应将表3更新为：

author_id    revenue
----------------------
   100          10
   200          20
   300          30

如果它们可以通过公用键直接链接到另一个表中，则可以更新另一个表中的值，而我不得不在中间引用另一个表以获取答案：（

我尝试过：

UPDATE table3 t3 SET revenue = 
(SELECT t1.margin FROM table1 t1 WHERE
(SELECT t1.book_id FROM table1 t1 JOIN table2 t2 ON t1.book_id = t2.book_id) = 
(SELECT author_id FROM table3 t3 JOIN table2 t2 ON t3.authoer_id = t2.author_id));

谢谢

Answer 1

使用update with join

update 
(
SELECT table3.revenue as OLD, table1.margin as NEW
FROM table1 INNER JOIN table2 on table1.book_id=table2.book_id
inner join table3 on table2.author_id=table3.author_id
)t set t.old=t.new

Answer 2

对子查询使用合并更新

 MERGE INTO table3 t3 
 using 
 (select t1.margin,t2.author_id
 from tabl1 t1 join table2 t2 on t1.book_id=t2.book_id
  ) a ON (t3.author_id = a.author_id)
 when matchced then
 update SET t3.revenue = a.margin

Answer 3

您也可以通过使用update方法来使用with..as：

update table3 t3
set t3.revenue = 
    (with t as (
                 select * 
                   from table1 t1
                   join table2 t2 on t2.book_id = t1.book_id
                )
                select t.margin from t where t.author_id = t3.author_id);

Demo

Oracle SQL：使用第三个表之间的另一个表更新表列

3 个答案: