基於聯接表向LINQ查詢添加計數列

Question

因此，我已經創建了一個SQL視圖，該視圖可以提供所需的信息。 從本質上講，這是一個工作職位空缺系統，用於顯示已批准或填補（或分配）了多少個職位。

SELECT Companies.Name AS Company, Grades.Name AS Grade, Series.Name
AS Series, Positions.Authorized, COUNT(People.PersonId) AS Assigned

FROM Companies INNER JOIN
     Positions ON Companies.Id = Positions.CompanyId INNER JOIN
     Series ON Positions.SeriesId = Series.Id INNER JOIN
     Grades ON Positions.GradeId = Grades.Id INNER JOIN
     People ON Positions.CompanyId = People.CompanyId AND
     Positions.SeriesId = People.SeriesId AND Positions.GradeId = People.GradeId

GROUP BY Companies.Name, Grades.Name, Series.Name, Positions.Authorized

現在，我想做的就是在LINQ查詢中重新創建它。 我幾乎在需要的地方得到它； 但是，我不知道如何在基於People表的末尾添加計數列。

這是我當前的LINQ查詢：

var query = from a in db.Companies
            join b in db.Positions on a.Id equals b.CompanyId
            join c in db.Series on b.SeriesId equals c.Id
            join d in db.Grades on b.GradeId equals d.Id
            join e in db.People on new { b.CompanyId, b.SeriesId, b.GradeId } equals new { e.CompanyId, e.SeriesId, e.GradeId }
            group a by new { CompanyName = a.Name, GradeName = d.Name, SeriesName = c.Name, b.Authorized, e.PersonId } into f
            select new { Company = f.Key.CompanyName, Grade = f.Key.GradeName, Series = f.Key.SeriesName, f.Key.Authorized, Assigned = /* needs to be Count(People.PersonId) based on last join */ )};

預先感謝您提供的任何幫助！

Answer 1

弄清楚了。 之所以發布多行而不是對同一行進行正確計數，是因為在我的“ group by”中，我應該在應該簡單刪除的情況下在“ e.PersonId”中添加它。 我還必須添加一些內容以使其在前端剃刀視圖上工作，因為它是匿名類型（這與原始問題無關，但以為我會給出更改的理由）。 所以刪除答案的人，您在某種程度上是正確的，但之所以無效，是因為該組中的其他字段：

dynamic query = (from a in db.Companies
                    join b in db.Positions on a.Id equals b.CompanyId
                    join c in db.Series on b.SeriesId equals c.Id
                    join d in db.Grades on b.GradeId equals d.Id
                    join e in db.People on new { b.CompanyId, b.SeriesId, b.GradeId } equals new { e.CompanyId, e.SeriesId, e.GradeId }
                    group a by new { CompanyName = a.Name, GradeName = d.Name, SeriesName = c.Name, b.Authorized } into f
                    select new { Company = f.Key.CompanyName, Grade = f.Key.GradeName, Series = f.Key.SeriesName, Authorized = f.Key.Authorized, Assigned = f.Count()}).AsEnumerable().Select(r => r.ToExpando());

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