使用 LinQ 的简单数学问题、简单的 Join 查询、Null 等

发布于 2024-08-11 04:59:48 字数 766 浏览 4 评论 0原文

我有 2 张桌子
1. 客户端
2. 操作

操作可能导致：贷项或借项（字符字段中的“C”或“D”）以及日期和金额字段。

我必须使用 linQ 计算每个客户帐户的余额...结果还应该为未进行操作的客户显示余额 0，但

我有以下带有 linQ 语句的函数，但我知道它可以以更好的方式完成更快、更短的路，对吧？会是哪一个？

public static double getBalance(ref ClasesDeDatosDataContext xDC, string SSN,
int xidClient)
{
    var cDebits =
        from ops in xDC.Operations
                where (ops.idClient == xidClient) && (ops.OperationCode == 'D')
                select ops.Ammount;
    var cCredits =
                from ops in xDC.Operations
                where (ops.idClient == xidClient) && (ops.OperationCode == 'C')
                select ops.Ammount;
    return (double)(cCredits.Sum() - cDebits.Sum());
}

谢谢！！！

原文

I have 2 tables
1. Client
2. Operations

Operations can result in: Credits or Debits ('C' or 'D' in a char field) along with date and ammount fields.

I must calculate the balance for each client's account using linQ... The result should also show balance 0 for clients whom didn't make operations yet

I have the following function with linQ statement, but I know it could be done in a better and quicker, shorter way, right? Which will be?

public static double getBalance(ref ClasesDeDatosDataContext xDC, string SSN,
int xidClient)
{
    var cDebits =
        from ops in xDC.Operations
                where (ops.idClient == xidClient) && (ops.OperationCode == 'D')
                select ops.Ammount;
    var cCredits =
                from ops in xDC.Operations
                where (ops.idClient == xidClient) && (ops.OperationCode == 'C')
                select ops.Ammount;
    return (double)(cCredits.Sum() - cDebits.Sum());
}

Thanks !!!

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

终难遇 2024-08-18 04:59:48

我不知道 LINQ-to-SQL 引擎是否可以处理该表达式，但类似这样的事情应该是可能的：

return (
  from ops in xDC.Operations
  where ops.idClient == xidClient
  select ops.operationCode == 'C' ? ops.Amount : -ops.Amount
).Sum(a => a);

或者也许：

return (
  from ops in xDC.Operations
  where ops.idClient == xidClient
  select new { Sign = ops.operationCode == 'C' ? 1.0 : -1.0, Amount = ops.Amount }
).Sum(o => o.Sign * o.Amount);

如果集合为空，则 Sum 方法返回零，这样就可以处理没有事务的客户端。

编辑：
更正查询中的拼写：Ampont ->数量

I don't know if the LINQ-to-SQL engine can handle the expression, but something like this should be possible:

return (
  from ops in xDC.Operations
  where ops.idClient == xidClient
  select ops.operationCode == 'C' ? ops.Amount : -ops.Amount
).Sum(a => a);

Or perhaps:

return (
  from ops in xDC.Operations
  where ops.idClient == xidClient
  select new { Sign = ops.operationCode == 'C' ? 1.0 : -1.0, Amount = ops.Amount }
).Sum(o => o.Sign * o.Amount);

If the collection is empty, the Sum method returns zero, so that takes care of clients without transactions.

Edit:
Corrected spelling in query: Ampont -> Amount

回复收藏 0 原文

~没有更多了~