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我正在尝试生成一个查询,以获取每个给定月份内出现日期的条目数。我希望生成的查询的 SQL 形式如下:

SELECT
DatePart(Year, [t1].[StartTime]) as Year,
DatePart(Month, [t1].[StartTime]) as Month,
Count(*) as 'Visits',
Sum([t1].[PageCount]) as 'Total Pageviews'
FROM
[MyDatabase] [t1]
GROUP BY
DatePart(Year, [t1].[StartTime]),
DatePart(Month, [t1].[StartTime])

我尝试了以下 Linq2DB 代码:

var query = from table in dataContext.MyDataContext(tablePath)
group table by new { table.StartTime.Year, table.StartTime.Month} into grp
select new { Month = grp.Key.Month, Year = grp.Key.Year,
TotalVisitors =   grp.Count(), 
TotalPageviews = grp.Sum(table2 => table2.PageCount) };

但由此生成的 SQL 查询是

--  SqlServer.2008  --
SELECT
[t1].[StartTime],
Count(*) as [c1],
Sum([t1].[PageCount]) as [c2]
FROM
[MyDatabase] [t1]
GROUP BY
DatePart(Year, [t1].[StartTime]),
DatePart(Month, [t1].[StartTime]),
[t1].[StartTime]

为什么是 [t1].[StartTime] 而不是月份或年份?为什么它最后会按额外的 [t1].[StartTime] 分组?如何使用 Linq2DB 生成上面的 SQL 查询?

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1 回答 1

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请对Sql.AsSql函数使用以下解决方法。我们正在努力解决这个长期存在的问题。

var query = from table in dataContext.MyDataContext(tablePath)
group table by new { Sql.AsSql(table.StartTime.Year), Sql.AsSql(table.StartTime.Month)} into grp
select new { Month = Sql.AsSql(grp.Key.Month), Year = Sql.AsSql(grp.Key.Year),
TotalVisitors =   grp.Count(), 
TotalPageviews = grp.Sum(table2 => table2.PageCount) }; 
于 2017-05-15T11:17:59.647 回答