更新中にカーソルを避ける

Question

+--------+-----------+-------+ 
| PartId | InvoiceId | Price | 
+--------+-----------+-------+ 
| 200 | 1000 | 10000 | 
| 201 | 1001 | 22000 | 
| 202 | 1002 | 30000 | 
+--------+-----------+-------+ 

+--------+-----------+-------+ 
| PartId | PaymentId | Price | 
+--------+-----------+-------+ 
| 200 | 1000 | 1000 | 
| 200 | 1001 | 3000 | 
| 201 | 1002 | 5000 | 
+--------+-----------+-------+ 

+-----------+-----------+-------------------------+ 
| InvoiceId | PaymentId | Balance Need to be Paid | 
+-----------+-----------+-------------------------+ 
| 1000  | 1000 | 9000     | 
| 1000  | 1001 | 6000     | 
| 1001  | 1002 | 17000     | 
+-----------+-----------+-------------------------+ 

カーソルはパフォーマンスがあまり良くありません。カーソルを使用しないと、請求書支払いマッピングテーブルを更新する方法はありますか？

Answer 1

これは1回の更新で実行できます。あなたの質問はすべての必要な詳細を持っていないので、以下はむしろ投機的です。

update ip 
    set BalanceToBePaid = (i.price - p.sumprice) 
from invoicepayment ip join 
    invoices i 
    on ip.invoiceid = i.invoiceid join 
    (select paymentid, sum(price) as sumprice 
     from payments 
     group by paymentid 
    ) p 
    on ip.payment = p.payment;