查询和聚合数据表的问题 [英] Problem with quering and aggregation of DataTable

问题描述

我对LINQ相对较新，我正在尝试查询DataTable并计算其中的2列之和，然后将结果按其余字段分组.问题是我只能获取聚合的列值，而不能获取非聚合的值.这是我正在使用的代码:

I am relatively new to LINQ and I am trying to query a DataTable and calculating sum of 2 columns in it and grouping the result by the rest of the fields. The thing is I can only get the aggregated column values and I can''t get the non aggregated values. Here''s the code I am using:

var balances = from b in dtAccounts.AsEnumerable()<br />                    group b by b.Field<decimal>("ACCOUNT_ID") into g<br />                    select new { credit = g.Sum(b => b.Field<decimal>("CREDIT")), debit = g.Sum(b => b.Field<decimal>("DEBIT")) };

有人可以给他一些提示，我只是选择由account_id分组的借方和贷方字段之和；问题是我不知道如何选择带有汇总结果的account_id列.

Can someone give a hint about his piece of code, I simply select sums of the fields debit and credit grouped by account_id; the problem is I don''t know how to select account_id column with the aggregated results.

推荐答案

范围变量g具有一个属性Key，该属性表示分组的关键字.在您的情况下，这是b.Field< decimal>("ACCOUNT_ID").因此，如果您想获得带有结果的account_id，则需要以下查询:

The range variable g has a property Key that represents the key that you have grouped by. In your case, this is b.Field<decimal>("ACCOUNT_ID"). So, if you want to have the account_id with the results, you need this query:

var balances = from b in dtAccounts.AsEnumerable()<br />               group b by b.Field<decimal>("ACCOUNT_ID") into g<br />               select new<br />                      {<br />                          accountId = g.Key,<br />                          credit = g.Sum(b => b.Field<decimal>("CREDIT")),<br />                          debit = g.Sum(b => b.Field<decimal>("DEBIT"))<br />                      }

希望这对您有所帮助

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