Get Maximum Value from multiple rows of multiple columns using LINQ? - linq

Question

I'm using LINQPad to evaluate my linq query. My query goes like this:
from o in MyTableFirst
join p in MyTableSecond on o.TheName equals p.TheName
where p.TheName == "CBA-123" && !p.Removed &&
(o.ReturnPeriod ==100 || o.ReturnPeriod ==10)
select new {
HMax1 = o.MaxValue1,
HMax2 = o.MaxValue2,
HMax3 = o.MaxValue3
}
This query can return 0 or some number of rows.
In LINQPad, it return me something like this:
HMax1 HMax2 HMax3
21.1 null 22.5
null 24.6 11.5
Now, how am I going to get the Maximum value out for these return rows & columns?
I'm expecting return of 24.6.Thank You

Answer 1

How about this:
(from o in db.MyTableFirsts
join p in db.MyTableSeconds on o.TheName equals p.TheName
where p.TheName == "CBA-123" && !p.Removed &&
(o.ReturnPeriod == 100 || o.ReturnPeriod == 10)
select new
{
Maximum = Math.Max(
Math.Max((float)(o.MaxValue1 ?? 0), (float)(o.MaxValue2 ?? 0)),
(float)(o.MaxValue3 ?? 0)
)
}).OrderByDescending(o => o.Maximum).FirstOrDefault();
Or instead of .OrderByDescending(o => o.Maximum).FirstOrDefault(), you can use .Max(o => o)

Answer 2

Try this:
(
from o in MyTableFirst
join p in MyTableSecond on o.TheName equals p.TheName
where p.TheName == "CBA-123" && !p.Removed &&
(o.Level ==100 || o.Level ==10)
//combine all of the numbers into one list
let listOfNumbers = new List<double?>{o.MaxValue1,o.MaxValue2,o.MaxValue3}
//select the list
select listOfNumbers
)
.SelectMany(c => c) //combine all the lists into one big list
.Max(c => c) //take the highst number