linq 為 C# 應用程序選擇不同和計數

Question

我有兩個 sql 查詢，我已經測試過兩個查詢都在工作。 我需要轉換為下拉列表的 Linq 查詢（MVC C#）。 有什么方法可以讓 Linq 查詢只顯示日期而不顯示時間？ 例如僅日期 2015-09-30

  SELECT DISTINCT DelDate  from Location where    
  DStatus = 'true' and FState = 'true' 

輸出

2015-09-30 14:06:37.000
2015-09-30 14:14:09.547

我的第二個查詢，我只需要轉換 linq 列表

SELECT COUNT(DISTINCT CouName) AS StatusCount  FROM Location  where   
DlStatus = 'true' and FState = 'true'  and CouName = 'Alan'

Answer 1

根據您問題中的SQL ，等效的Linq將是

SELECT DISTINCT DelDate from Location where DStatus = 'true' and FState = 'true'

var delDates = Location
  .Where(l => l.DStatus == "true" && l.FState == "true")
  .Select(f => f.DelDate)
  .Distinct();

SELECT COUNT(DISTINCT CouName) AS StatusCount FROM Location where DlStatus = 'true' and FState = 'true' and CouName = 'Alan'

var statusCount = Location
  .Where(l => l.DStatus == "true" && l.FState == "true" && l.CouName == "Alan")
  .Select(f => f.CouName)
  .Distinct()
  .Count();

Answer 2

這個

db.Location.Where(x=>x.DStatus == "true" && x.FState == "true")
           .Select(y=>y.DelDate.Value.ToString("yyyy-MM-dd")).Distinct().ToList();

和這個

    db.Location.Where(x=>x.DStatus == "true" && x.FState == "true" && x.CouName == "Alan")
               .Select(y=>y.CouName).Distinct().Count();

Answer 3

對於僅獲取日期的第一個查詢，您可以在選擇時截斷時間.Date將僅獲取日期並刪除時間部分。

var dates = Location.Where(l => l.DStatus && l.FState)
                    .Select(f => f.DelDate.Date)
                    .Distinct();

對於第二個查詢

var count = Location.Where(l => l.DStatus && l.FState && l.CouName == "Alan")
                    .Select(f => f.CouName)
                    .Distinct()
                    .Count();