将 SQL 查询转换为 LINQ - DateDiff 函数

Question

我的任务是使用 Groupby、Orderby、Date 函数将以下 SQL 查询转换为 LINQ。

SELECT 
       sd.name, s.BuilderName,
       Min(Date) as MinDatetime, 
       Max(Date) as MaxDatetime, 
       datediff(day, min(Date), max(Date))/ cast (count(sd.jobRobosname) as float) 
FROM 
       [Data] sd  
JOIN Example s ON s.name= sd.Name
WHERE jobRobosjobid='NOT RUN' 
GROUP  BY sd.name, s.name

我试过了，

(from record in _db.Data                              
join jobRobos in _db.Example on record.Name equals Example.Name
where record.jobRobos jobid != "NOT RUN"
  group jobRobos by new {record.Name,jobRobos .BuilderName} into r
select new
{
    jobRobos Name = r.Key.jobRobos Name,
    BuilderName = r.Key.BuilderName,
    MaxDate = r.Key.Min(r.Date),
    MinDate = r.Max(c => c.Date),
    Diff = r.Key.datediff(day, MinDate, MaxDate) / r.Key.Cast(Count(r.Key.jobRobos Name) as float)
}).ToList();

我在这里提到了一些类似的问题，例如：

• How to convert SQL query into LINQ
• Convert SQL query into linq to entities
• Convert SQL query into LINQ query in VB
• Translate SQL Query into LINQ Query

但找不到解决方案。

谁能给我一些建议？

Answer 1

对于 EF 6，这应该可以使用 DbFunctions.DiffDays:

(from record in _db.Data                              
join spider in _db.Example on record.Name equals Example.Name
where record.spiderjobid != "NOT RUN"
  group spider by new {record.Name,spider.BuilderName} into r
select new
{
    Name = r.Key.Name,
    BuilderName = r.Key.BuilderName,
    MaxDate = r.Max(d => d.Date),
    MinDate = r.Min(d => d.Date),
    Diff = DbFunctions.DiffDays(r.Max(d => d.Date), r.Min(d => d.Date)) / r.Count(d => d.SpiderName)
}).ToList();