Question

I am looking for a way in C# LINQ using lambda format to group records per second. in my search i have yet to find a good way to do this.

the SQL query is as follows.

select count(cct_id) as 'cnt'
  ,Year(cct_date_created) 
  ,Month(cct_date_created) 
  ,datepart(dd,cct_date_created) 
  ,datepart(hh,cct_date_created) 
  ,datepart(mi,cct_date_created) 
  ,datepart(ss,cct_date_created) 
from ams_transactions with (nolock)
where cct_date_created between dateadd(dd,-1,getdate()) and getdate()
group by 
  Year(cct_date_created)
  ,Month(cct_date_created)
  ,datepart(dd,cct_date_created)
  ,datepart(hh,cct_date_created)
  ,datepart(mi,cct_date_created)
  ,datepart(ss,cct_date_created)

now the closest i was able to come was the following but it is not giving me the right results.

var groupedResult = MyTable.Where(t => t.cct_date_created > start 
                                    && t.t.cct_date_created < end)
                           .GroupBy(t => new { t.cct_date_created.Month,
                                               t.cct_date_created.Day,
                                               t.cct_date_created.Hour,
                                               t.cct_date_created.Minute, 
                                               t.cct_date_created.Second })
                           .Select(group => new { 
                                                 TPS = group.Key.Second
                                                });

this appears to be grouping by seconds but not considering it as per individual minute in the date range and instead that second of every minute in the date range. To get Transactions per second i need it to consider each minute of the month, hour, day, minute separately.

The goal will be to pull a Max and Average then from this grouped list. Any help would be greatly appreciated 🙂

Answer 1

Currently you’re selecting the second, rather than the count – why? (You’re also using an anonymous type for no obvious reason – whenever you have a single property, consider just selecting that property instead of wrapping it in an anonymous type.)

So change your Select to:

 .Select(group => new { Key = group.Key,
                        Transactions = group.Count() });

Or to have all of the key properties separately:

 .Select(group => new { group.Month,
                        group.Day,
                        group.Hour,
                        group.Minute,
                        group.Second,
                        Transactions = group.Count() });

(As an aside, do you definitely not need the year part? It’s in your SQL…)