Entity Core 2.0.3 异常：必须是可简化节点

Question

我正在尝试将以下 sql 查询转换为 EF

sql 查询

Select  Sum([KiloWatt]) as 'Sum',
    Min([KiloWatt]) as 'Min',
    Max([KiloWatt]) as 'Max',
    Sum([KiloWatt])/COUNT([KiloWatt]) as 'Average',
    CONVERT(date, [DateTime]) 
from OneHourElectricitys 
where [DateTime] < SYSDATETIME()
group by CONVERT(date, [DateTime])

EF 代码

var analytics = await _analyticsRepository.Query().Where(x => x.DateTime.Subtract(DateTime.Today).Days < 0)
                                                  .GroupBy(x => x.DateTime.Date)
                                                  .Select(x => new 
                                                    { DateTime = x.Key, 
                                                      Max = x.Max(y => y.KiloWatt),
                                                      Min = x.Min(y => y.KiloWatt),
                                                      Avg = x.Sum(y => y.KiloWatt)/ x.Count(),
                                                      Sum = x.Sum(y => y.KiloWatt)
                                                    })
                                                  .ToListAsync();

堆栈跟踪：-

System.ArgumentException: must be reducible node at System.Linq.Expressions.Expression.ReduceAndCheck() at System.Linq.Expressions.Expression.ReduceExtensions()

我是不是做错了？

-- 更新--

以下 2 个 EF 查询运行没问题，但合并它们会出现错误。

var analytics = await _analyticsRepository.Query().Where(x => x.DateTime.Subtract(DateTime.Today).Days < 0)

var analytics = await _analyticsRepository.Query().GroupBy(x => x.DateTime.Date)
                                              .Select(x => new 
                                                { DateTime = x.Key, 
                                                  Max = x.Max(y => y.KiloWatt),
                                                  Min = x.Min(y => y.KiloWatt),
                                                  Avg = x.Sum(y => y.KiloWatt)/ x.Count(),
                                                  Sum = x.Sum(y => y.KiloWatt)
                                                })
                                              .ToListAsync();

Answer 1

这是我的解决方案并且有效。

var analytics = await (_analyticsRepository.Query()
                .Where(x => x.PanelId.Equals(panelId, StringComparison.CurrentCultureIgnoreCase)
                && DateTime.Compare(x.DateTime, new DateTime()) < 0))
            .GroupBy(x => x.DateTime.Date)
                .Select(x => new
                {
                    DateTime = x.Key,
                    Max = x.Max(y => y.KiloWatt),
                    Min = x.Min(y => y.KiloWatt),
                    Avg = x.Sum(y => y.KiloWatt) / x.Count(),
                    Sum = x.Sum(y => y.KiloWatt)
                }).ToListAsync();

谢谢，

Answer 2

如 Ivan Stoev 所述，此问题的正确解决方案是升级到 EF Core 2.1.3

Answer 3

使用

 DateTimeField.Year +""+ DateTimeField.Month  //Use this

而不是 使用自定义日期格式，例如

 DateTimeField.ToString("yyyy - MM") //Don't use this

为我解决了问题

顺便说一句，我的 .net 核心版本是 2。2.x

Entity Core 2.0.3 异常：必须是可简化节点

Entity Core 2.0.3 Exception: must be reducible node

c#

entity-framework

entity-framework-core

ef-core-2.0