How to get a group ordered by the count column
It is hard to ask the question in plain english so I'll show what I'm trying to do.
Here's my SQL code:
select top 100 [Name], COUNT([Name]) as total from ActivityLog
where 1674380443 between '2010-10-28' and '2010-10-29 17:00'
group by [Name]
order by total desc
I need to write that in LinQ. So far I have the following:
var group开发者_Go百科s = from ActivityLog log in ctx.ActivityLog
where log.Timestamp > dateFrom
where log.Timestamp <= dateTo
group log by log.Name;
but I don't have the COUNT(*)
column to sort from :(
I'm afraid I am far more comfortable with the fluent syntax (as opposed to query syntax), but here is one possible LINQ answer:
ctx.ActivityLog
.Where(x => x.TimeStamp > dateFrom && x.TimeStamp <= dateTo)
.GroupBy(x => x.Name)
.Select(x => new { Name = x.Key, Total = x.Count() })
.OrderByDescending(x => x.Total)
.Take(100)
EDIT:
Alright, I stepped out of my comfort zone and came up with a query syntax version, just don't expect too much. I warned you about my abilities above:
(from y in (
from x in (
from log in ActivityLog
where log.Timestamp > dateFrom
where log.Timestamp <= dateTo
group log by log.Name)
select new { Name = x.Key, Total = x.Count() })
orderby y.Total descending
select new { Name = y.Name, Total = y.Total }).Take(100)
diceguyd30's answer technically is LINQ and is correct. In fact, the query syntax gets translated to those Queryable/Enumerable methods by the compiler. That said what's missing is using the group ... by ... into
syntax. The equivalent query should be close to this:
var query = from log in ctx.ActivityLog
where log.TimeStamp > dateFrom && log.TimeStamp <= dateTo
group log by log.Name into grouping
orderby grouping.Count() descending
select new { Name = grouping.Key, Total = grouping.Count() };
var result = query.Take(100);
Note that in C# the Take(100)
method has no equivalent in query syntax so you must use the extension method. VB.NET, on the other hand, does support Take
and Skip
in query syntax.
精彩评论