Linq to SQL combination of aggregate functions - sql

Question

Is there a way to simplify this and make it go faster?
In SQL I use count(*) and count(distinct) in same query which gives me a faster result
Thanks a bunch.
int numberOfUsers = (from u in db.UseLogs
where u.DocID == docID
&& u.LogDate >= fromDate
&& u.LogDate <= to
select u.UserID).Distinct().Count();
int numberOfVisits = (from u in db.UseLogs
where u.DocID == docID
&& u.LogDate >= fromDate
&& u.LogDate <= to
select u).Count();
Conclusion
There is no Count( Distinct) in LINQ. Not EVERY SQL statement can be translated into LINQ.
Thanks for the help guys!

Answer 1

Is this what you're looking for?
from u in db.UseLogs
where u.DocId == docId && u.LogDate >= fromDate && u.LogDate <= to
group u by true into g
select new
{
Count = g.Count(),
DistinctUserCount = g.Select(x => x.UserId).Distinct().Count()
}
You will want to check if it's actually faster than running two queries, or if the performance gain is worth the loss of readability.

Answer 2

Not exactly what you're trying to acheive but may be just as fast:
var query =
from u in db.UseLogs
where u.DocId == docId && u.LogDate >= fromDate && u.LogDate <= to
group u by u.UserID into g
select new
{
Visits = g.Count()
};
int numberOfUsers = query.Count();
int numberOfVisits = query.Sum(q=>q.Visits);
It executes the SQL only once and does the SUMming in memory.