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Count and Max Columns Group By in LINQ

I have model
public class Rate
{
public int Nr{ get; set; }
public string Rate{ get; set; }
public int Order{ get; set; }
}
and a RateList = List<Rate> like this
Nr | Rate | Order
123 | A | 2
425 | A+ | 1
454 | B | 4
656 | B+ | 3
465 | A | 2
765 | B | 4
Notice that Order always match the Rate (A+ = 1, A = 2, B+ = 3, B = 4, C+ = 5 ...)
I want to count how many time the Rate occoured and display order by the Order
The result should look like this
Rate | Count | Order
A+ | 1 | 1
A | 2 | 2
B+ | 1 | 3
B | 2 | 4
or without column Order
Rate | Count
A+ | 1
A | 2
B+ | 1
B | 2
In SQL I could do like this if I had above list in table Tab
SELECT Rate, COUNT(Rate), Max(Order) from Tab group by Rate
but in LINQ?
I was trying something like this
var rating= RateList.Distinct().GroupBy(x => x.Rate)
.Select(x => new { Rate = x.Key, RateCount = x.Count() })
.OrderBy(x => x.Order);
but didnt work.
Thank You for help.

Your SQL query is equevalent to:
var rating = rateList.GroupBy(x => x.Rate)
.Select(x => new {
Rate = x.Key,
RateCount = x.Count(e => e != null),
Max = x.Max(g => g.Order)
});

Converting SQL to Linq query

I'm trying to get the output of the following query into a Linq query
SELECT SearchQueries.Query,
Clicks.Name,
COUNT (SearchQueries.Query) AS Hits
FROM SearchQueries
INNER JOIN Clicks ON Clicks.SearchqueryId = SearchQueries.Id
GROUP BY SearchQueries.Query, Clicks.Name
ORDER BY Hits DESC
But I can't seem to figure out how to do this;
this is what I have so far
var result =
_db.Clicks.Select(q => q)
.GroupBy(q => q.Name, g => g.Searchquery.Query)
.ToDictionary(g=> g.Key, g => g);
but how would I continue?
the result is something like this:
+---------------+-------------------+------+
|Query | Name | Hits |
+---------------+-------------------+------+
|tag | dnfsklmfnsd | 53 |
|tag2 | dgsqfsdf | 17 |
+---------------+-------------------+------+
The original tables looks like following
SearchQueries;
+---+-------+
|Id | Query |
+---+-------+
| 1 | tag | x 53
| 2 | tag2 | x 17
+---+-------+
Clicks;
+---+-------------------+---------------+
|Id | Name | SearchqueryId |
+---+-------------------+---------------+
| 1 | dnfsklmfnsd | 1 |
| 2 | dgsqfsdf | 2 |
+---+-------------------+---------------+

Try to use GroupBy and Count: (I changed the order to using SearchQueries as "base table" in the expression, just to make it more easy to compare to the SQL-statement)
var result =
_db.SearchQueries
.GroupBy(sq => new { name = sq.Clicks.Name, query = sq.Query)
.Select(sq => new {
Query = sq.Query,
Name = sq.Clicks.Name,
Hits = sq.Count()
})
.OrderByDescending(sq => sq.Hits);

Well, if you have a navigation property Searchquery on Click, as it looks like, you can do
var result =
_db.Clicks
.GroupBy(m => new {name = m.Name, query = m.Searchquery.Query)
.Select(g => new {
Query = g.Key.query,
Name = g.Key.name,
Hits = g.Count()
});

Select all columns but group by only one in linq

I have been looking for a way to get multiple columns but group by only one in SQL and I found some info. However I can not came up with a way to do it in linq.
I have the following toy example table:
| Id | Message | GroupId | Date |
|-------------------------------|
| 1 | Hello | 1 | 1:00 |
| 2 | Hello | 1 | 1:01 |
| 3 | Hey | 2 | 2:00 |
| 4 | Dude | 3 | 3:00 |
| 5 | Dude | 3 | 3:01 |
And I would like to recover all columns for the rows that have a distinct GroupId as follows (with a 'Date' desc order):
| Id | Message | GroupId | Date |
|-------------------------------|
| 1 | Hello | 1 | 1:00 |
| 3 | Hey | 2 | 2:00 |
| 4 | Dude | 3 | 3:00 |
I do not really care about which row is picked from the grouped ones (first, second...) as long as is the only one given that group Id.
I have came out with the following code so far but it does not do what is supposed to:
List<XXX> messages = <MyRep>.Get(<MyWhere>)
.GroupBy(x => x.GroupId)
.Select(grp => grp.OrderBy(x => x.Date))
.OrderBy(y => y.First().Date)
.SelectMany(y => y).ToList();

This will give you one item per group:
List<dynamic> data = new List<dynamic>
{
new {ID = 1, Message = "Hello", GroupId = 1, Date = DateTime.Now},
new {ID = 2, Message = "Hello", GroupId = 1, Date = DateTime.Now},
new {ID = 3, Message = "Hey", GroupId = 2, Date = DateTime.Now},
new {ID = 4, Message = "Dude", GroupId = 3, Date = DateTime.Now},
new {ID = 5, Message = "Dude", GroupId = 3, Date = DateTime.Now},
};
var result = data.GroupBy(item => item.GroupId)
.Select(grouping => grouping.FirstOrDefault())
.OrderByDescending(item => item.Date)
.ToList();
//Or you can also do like this:
var result = data.GroupBy(item => item.GroupId)
.SelectMany(grouping => grouping.Take(1))
.OrderByDescending(item => item.Date)
.ToList();
If you want to control OrderBy then:
var result = data.GroupBy(item => item.GroupId)
.SelectMany(grouping => grouping.OrderBy(item => item.Date).Take(1))
.OrderByDescending(item => item.Date)
.ToList();

How to add List<T> containing item of type List<string> ,int,string into another List

I have a list with complex data
public class CAR
{
public int ID {get ; set ; }
public string Name { get ; set ; }
public string EngineType { get ; set ; }
public List<string> Months { get; set; }
}
Note that Months data is List<string> its max count is 150
List<CAR> A = new List<CAR>();
List<CAR> B = new List<CAR>();
A has follwoing data
ID | Name | EngineType | Months[0] | Months[1] | Months[2] | Months[3] .. | Months[149] |
1 | Zen | 1001 | 1 | 1 | 4 | 5 .. | 6 |
2 | Benz | 2002 | 6 | 4 | 5 | 6 .. | 2 |
3 | Zen | 1001 | 3 | 1 | 7 | 5 .. | 0 |
4 | Zen | 1001 | 2 | 2 | 4 | 5 .. | 6 |
5 | Zen | 2002 | 2 | 2 | 4 | 5 .. | 6 |
6 | Benz | 2002 | 1 | 1 | 1 | 1 .. | 1 |
IF EngineType and Name are same we add those rows and store the result in a single row
Eg : adding rows
row 1 in B = 1 + 3 + 4
row 2 in B = 2 + 6
row 3 in B = 5
B should contain the following op
ID | Name | EngineType | Months[0] | Months[1] | Months[2] | Months[3] ... | Months[149] |
- | Zen | Petrol | 6 | 4 | 15 | 15 .. | 12 |
- | Benz | Diesel | 7 | 5 | 6 | 7 | 3 |
- | Zen | Diesel | 2 | 2 | 4 | 5 .. | 6 |
had months data been separate entity of type integer something else i could have done this
B = from val in A
group val by new val.EngineType into g
select new CAR{
EngineType = g.Key,
Name = g.Name,
Month0 = g.Sum(p => p.Month0),
Month1 = g.Sum(p => p.Month1),
Month2 = g.Sum(p => p.Month2),
.
.
.
.
.
.
Month148 = g.Sum(p => p.Month148),
Month149 = g.Sum(p => p.Month149)
}.ToList<CAR>();
But since its of type List<string> is there a way to get this done?
Thanks a lot!

Use the power of LINQ:
var B = A.GroupBy(x => new { x.Name, x.EngineType })
.Select(g => new Car
{
Name = g.Key.Name,
EngineType = g.Key.EngineType,
Months = g.SelectMany(x => x.Months.Select((y,i) => new { i, y = int.Parse(y) }))
.GroupBy(x => x.i)
.OrderBy(g2 => g2.Key)
.Select(g2 => g2.Sum(x => x.y).ToString()).ToList()
}).ToList();

foreach (CAR c in A)
{
bool blnadded = false;
if (B.Count == 0)
{
B.Add(c);
blnadded = true;
}
else
foreach (CAR d in B)
{
if (d.Name == c.Name && d.EngineType == c.EngineType)
{
for (int i = 0; i < d.Months.Count; i++)
d.Months[i] = (Convert.ToInt32(d.Months[i]) + Convert.ToInt32(c.Months[i])).ToString();
blnadded = true;
}
}
if (blnadded==false)
B.Add(c);
}

c# / Linq sum where

I have a table NCR containing data of the format:
ID | Date | Item | Type | Qty
1 | 01/01/13 | Apple | A | 1
2 | 01/01/13 | Apple | B | 1
3 | 01/01/13 | Orange | C | 1
4 | 01/01/13 | Orange | A | 2
6 | 01/01/13 | Orange | C | 1
I would like to produce a linq query that gives me a summary of the types and sums for a given date like so:
Item | A | B | C
Apple | 1 | 1 | 0
Orange | 2 | 0 | 2
So far I have this:
var q = data.GroupBy(l => l.Item)
.Select(g => new {
Item = g.Key,
Total = g.Sum(c => c.Qty),
A = g.Sum(c => c.Type == "A"),
B = g.Sum(c => c.Type == "B"),
C = g.Sum(c => c.Type == "C")
});
However I can't seem to give a criteria to the g.Sum lambda statement. If I use Count (which is the wrong data) I can give the critera, but why is Sum missing this? What is my alternative to creating a summary table of the data available?

The delegate provided to Sum isn't a predicate; it's a selector.
Are you trying to sum the Qty property? If so, I suspect you want:
A = g.Where(c => c.Type == "A").Sum(c => c.Qty),
B = g.Where(c => c.Type == "B").Sum(c => c.Qty),
C = g.Where(c => c.Type == "C").Sum(c => c.Qty)
(Or you could group by type as well, of course.)