LINQ的SQL命令（旋轉）

Question

我正在將數據庫從MySQL（使用ODBC）轉移到MS SQL，我想將SQL查詢“轉換”為LINQ。 有人可以幫我這個（它應該為每個位置的SUM Charge列和幾個月的組結果）：

SELECT
sum(case when Location="Location1" then Charge else 0 end) as Location1,
sum(case when Location="Location2" then Charge else 0 end) as Location2,
sum(case when Location="Location3" then Charge else 0 end) as Location3,
MAKEDATE(YEAR(OrderTime),DAYOFYEAR(OrderTime)) AS date FROM Sales
GROUP BY YEAR(OrderTime),MONTH(OrderTime)
ORDER BY OrderTime DESC 

？

輸出應如下所示：

Location1 | Location2 | Location3 | date

編輯：

我試着從這里使用LINQ示例：

是否可以使用LINQ旋轉數據？

var query = context.log_sales
                            .GroupBy(c => c.OrderTime)
                            .Select(g => new
                            {
                                Date = g.Key,
                                Location1 = g.Where(c => c.Location == "Location1").Sum(c => c.Charge) ?? 0,
                                Location2 = g.Where(c => c.Location == "Location2").Sum(c => c.Charge) ?? 0
                            }).ToList();

這幾乎是我的需要。 應該按年分組，我不知道該怎么做。

Answer 1

這可能有所幫助。

context.log_sales
.GroupBy(s => new {Year = OrderTime.Year, Month = OrderTime.Month})
.Select
( g => new {
  Date = new DateTime(g.Key.Year, g.Key.Month, 1),
  Location1 = g.Where(s => s.Location == "Location1").Sum(s => s.Charge),
  Location2 = g.Where(s => s.Location == "Location2").Sum(s => s.Charge),
  Location3 = g.Where(s => s.Location == "Location3").Sum(s => s.Charge),
  }
)
.OrderBy(x => x.Date);

Answer 2

..你知道如何動態添加Locations to Select嗎？ 例如，從List / Array。

編輯：..或者可能使位置動態加載並設置應在Select之前的Where語句中加載哪些位置。 這可能嗎？