C# 如何将项目的发票总额更新为两列之一，即IS或Business

我有两张桌子：

一个是发票表，它有一个名为

BusinessOrIS

的查找表，以确定它是“is”还是“Business”；以及一个表示发票金额的已用列

另一个表是projects表，它有两列需要更新“TotalIsPent”和“TotalBusinessPend”

所以我想做的是取BusinessOrIS=1（is）和invoice.projectd=Projects.projectd的花费金额之和。以及BusinessOrIS=2（Business）和invoice.projectd=Projects.projectd。并将其汇总到“TotalIsPent”和“TotalBusinessPend”

//我现在看到的是InsertButton点击事件的c侧：

//进入公司

SqlConnection db = new SqlConnection("mystring")SqlTransaction transaction;
db.Open()
transaction = db.BeginTransaction();
UPDATE Projects Set ProjectSpentIS = (SELECT SUM(Invoices.Spent) 
FROM Invoices WHERE Invoices.CostToISorBusiness ='1' 
AND Projects.Projectid = Invoices.ProjectID)

UPDATE Projects Set ProjectSpentBusiness = 
(SELECT SUM(Invoices.Spent) FROM Invoices
    WHERE Invoices.CostToISorBusiness ='2' AND 
    Projects.Projectid = Invoices.ProjectID)
transaction.Commit();

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我想我可能对您的模式设计有问题（因为您似乎有一个多域表，这是一个禁忌，或者至少应该为将来的扩展设置数据库）。但是，您没有发布足够的信息来重新推荐更改

但是，您应该能够将

UPDATE

重新表述为一条SQL语句：

UPDATE Projects as a 
SET ProjectSpentIS = COALESCE((SELECT SUM(b.Spent)
                               FROM Invoices as b
                               WHERE b.CostToISOrBusiness = '1'
                               AND b.ProjectId = a.ProjectId), ProjectSpentIS),
    ProjectSpentBusiness = COALESCE((SELECT SUM(b.Spent)
                                     FROM Invoices as b
                                     WHERE b.CostToISOrBusiness = '2'
                                     AND b.ProjectId = a.ProjectId), 
                                   ProjectSpentBusiness)
WHERE EXISTS (SELECT '1'
              FROM Invoices as b
              WHERE b.ProjectId = a.ProjectId
              AND b.CostToISOrBusiness in ('1', '2'))

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作为一点建议，您可能希望将事务代码包装在try{}catch{}中。如果出现错误，请在catch部分执行回滚，您在哪里分配SqlCommand来执行查询。。？还将事务对象分配给sql comman对象，例如sqlcmd.transaction=transaction；确保将sqlcmd创建为sqlcmd=newsqlcommand（）；您是否收到错误数据？如果没有更新，你能发布你的表模式和数据片段吗？很抱歉，我正在开会，我会在明天早上再次尝试发布你要求的内容。抱歉，耽搁了！谢谢！对不起，不，不！