Question

我正在将数据库从MySQL（使用ODBC）转移到MS SQL，我想将SQL查询“转换”为LINQ。有人可以帮我这个（它应该为每个位置的SUM Charge列和几个月的组结果）：

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

输出应如下所示：

Location1 | Location2 | Location3 | date

编辑：

我尝试从这里使用LINQ示例：

Is it possible to Pivot data using LINQ?

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();

这几乎是我的需要。应该按年分组，我不知道该怎么做。

Answer 1

这可能会有所帮助。

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

..你知道如何动态添加Locations to Select吗？例如，从List / Array。

编辑：..或者可能使Locations动态加载并设置应该在Select之前的Where语句中加载哪些Locations。这可能吗？

LINQ的SQL命令（旋转）

2 个答案: