Question

我试图在C＃中使用Linq2Db生成一个sql查询。我想要生成的查询是：

SELECT
   cast([t1].[StartTime] as date) as [StartTime1],
   Count(*) as [WebpageVisits],
   Sum([t1].[PageCount]) as [SumOfViewsOfPages]
          FROM
                 [myserver].[dbo].[TrackData] [t1]
   GROUP BY cast([t1].[StartTime] as date)

我试图使用的Linq代码是：

var query = from table in dataContext.TrackData(tablePath)
                        group table by new { table.StartTime.Date } into grp
                        select new { day = grp.Key.Date, numVisitors = grp.Count(), totalPageViews = grp.Sum(table2 => table2.PageCount)};

返回的查询是

    --  SqlServer.2008
SELECT
    [t1].[StartTime],
    Count(*) as [c1],
    Sum([t1].[PageCount]) as [c2]
FROM
    [myserver].[dbo].[TrackData] [t1]
GROUP BY
    Convert(Date, [t1].[StartTime]),
    [t1].[StartTime]

为什么会出现额外的[t1]。[StartTime]？这导致结果不会根据日期进行分组。如何生成我尝试使用Linq生成的SQL查询？

Answer 1

尝试分组删除匿名类型：

group table by table.StartTime.Date into grp

如果要按多列分组，则应使用匿名类型。我试过你在LinqPad中查询而我无法模拟相同的行为，但这是你应该遵循的原则

仅按Linq2DB中的日期进行分组

1 个答案: