在SQL Server数据库中,我有一个包含日志条目的表 - timestamp
和description
。
我需要按指定的时间间隔(30分钟)获取日志。
E.g:
01.01.2015 00:00 - 100
01.01.2015 00:30 - 200
01.01.2015 01:00 - 2
依旧......
我有什么:
var logs = session.Query<Log>;
//... other operations on logs queryable
var intervalInMinutes = 30;
var logsFrequency = logs
.GroupBy(l => new
{
Year = l.LogTimestamp.Year,
Month = l.LogTimestamp.Month,
Day = l.LogTimestamp.Day,
Hour = l.LogTimestamp.Hour,
Minute = (l.LogTimestamp.Minute / intervalInMinutes) * intervalInMinutes,
})
.Select(g => new LogsOccurence()
{
StartingDatetime = new DateTime(g.Key.Year, g.Key.Month, g.Key.Day, g.Key.Hour, g.Key.Minute, 0),
Frequency = g.Count()
})
.ToList();
以下查询失败:
类型的例外&#39; NHibernate.Exceptions.GenericADOException&#39;发生在NHibernate.dll但未在用户代码中处理
其他信息:无法执行查询
内部异常:列&#39; dbo.Log.LogTimestamp&#39;在选择列表中无效,因为它不包含在聚合函数或GROUP BY子句中。
生成的select语句是:
select
datepart(year, Log0_.LogTimestamp) as col_0_0_
, datepart(month, Log0_.LogTimestamp) as col_1_0_
, datepart(day, Log0_.LogTimestamp) as col_2_0_
, datepart(hour, Log0_.LogTimestamp) as col_3_0_
, datepart(minute, Log0_.LogTimestamp) as col_4_0_
, cast(count(*) as INT) as col_5_0_
from
dbo.[Log] Log0_
group by
datepart(year, Log0_.LogTimestamp)
, datepart(month, Log0_.LogTimestamp)
, datepart(day, Log0_.LogTimestamp)
, datepart(hour, Log0_.LogTimestamp)
, datepart(minute, Log0_.LogTimestamp)/@p0*@p1
Name:p1 - Value:30 Name:p2 - Value:30
groupby
子句
datepart(minute, Log0_.LogTimestamp) / @p0 * @p1
分钟的选择部分与分组的部分不同 - 选择失败
我的Linq有什么问题,以及如何写出正确的?
我正在使用NHibernate build 4.0.4.GA。