根据另一个表中的列更新数据库表中的列

Question

我有两张桌子

T1
|id|balance|
|1| 1000  |
|2| 2000  | 
|3| 3000  |

T2
|id|rate|months|
|1|0.50| 10   |
|2|0.25| 24   |
|3|0.40| 16   |

我想将表T1中的余额列更新为

T1.Balance = T1.Balance + T2.rate*T2.months*T1.Balance

如何在MS SQL服务器中执行此操作？谢谢！

Answer 1

以下查询可以帮助您使用单个查询更新特定列的所有行。

UPDATE T1 AS t1 SET t1.balance = t1.balance * (SELECT t2.rate * t2.months FROM T2 AS t2 WHERE t2.id = t1.id);

或者你也可以尝试这个

UPDATE T1 AS t SET t.balance = (t1.balance * t2.rate * t2.months) FROM T1 AS t1 JOIN T2 AS t2 ON t1.id = t2.id;