实体框架:返回按值和同一查询中某些列的总和进行分组

Question

我有一个表,我想在实体框架工作中执行以下操作:

1-从对象返回一些列而不是所有列(我为这个新类型创建了新类,只包含我需要的列,并在select语句中返回其中的值.

2-返回列应按某些列分组,其中两列将包含计数值.(这是我的问题).

有关更多说明:我需要在Entity Framework中对我的数据集的可共享对象映射以下查询:

select SUM (Col1) SUM_Col1, SUM (Col2) SUM_Col2, COUNT (*) RECORDS, Col3, Col4, Col5
from myTable
where col3 = 'some value'
group by Col3, Col4, Col5;

我的分组审判如下:

        query = from record in context.tables
                group record by new
                {
                    record.Col3,
                    record.Col4,
                    record.Col5,
                } into g
                select new QueryResult
                {
                    Col1 = (need Sum of Col1 here),
                    Col2 = (need Sumn of Col2 here),
                    Col3 = g.Key.Col3,
                    Col4 = g.Key.Col4,
                    Col5 = g.Key.Col5,
                    Col6 = ( need count of grouped records here)

                };

Answer 1

使用总和和计数

 query = from record in context.tables
                group record by new
                {
                    record.Col3,
                    record.Col4,
                    record.Col5,
                } into g
                select new QueryResult
                {
                    Col1 = g.Sum(x => x.Col1),
                    Col2 = g.Sum(x => x.Col2),
                    Col3 = g.Key.Col3,
                    Col4 = g.Key.Col4,
                    Col5 = g.Key.Col5,
                    col6 = g.Count()

                };