如何計算一個表中的總和，然后插入到另一個表中？

Question

我有兩張桌子。 第一張表：順序

|id   |total|
|A001 |     |
|A002 |     |

第二張表：商品

|id   |price|order_id|
|B001 |100  |A001    |
|B002 |200  |A001    |
|B003 |300  |A002    |

現在如何寫SQL語句計算goods表中有相同order_id的SUM價格，然后插入到order表的total列中，像這樣：

|id   |total|
|A001 |300  |
|A002 |300  |

Answer 1

Update O 
SET O.total = t.Sum_Of_Price
FROM Order AS O 
INNER JOIN 
    (
        Select order.id as ID, sum(goods.price) as Sum_Of_Price
        from goods 
        INNER JOIN order 
        ON order.id = goods.order_id  
        group by order.id
    ) t 
    ON O.id = t.id 

Answer 2

with temp(id, total) as (select order_id, sum(price) from goods group by order_id) update order o join temp t on o.id = t.id set o.total = t.total;

select * 來自order ；

在這里試試 https://www.db-fiddle.com/f/caceQG8i4dWKZjUfhGRi2R/0

Answer 3

我發現'order'是sql中的關鍵字，所以我將第一個表名更改為'orders'。

update orders a 
set total=
    (
        select sum(price) 
        from goods b 
        where a.id=b.order_id
    ) 
where exists 
    (
        select 1 
        from goods b 
        where a.id=b.order_id
    )