Question

I have following two tables:

DocumentType
    Id INT,
    Name VARCHAR(100),
    Active BIT,
    CreatedBy INT

Document
    Id INT,
    DocumentTypeId INT,
    Version SMALLINT,
    Text NTEXT

I want to select DocumentType and related Document record with maximum value for Version. I tried following query:

from t in Documents 
join tt in DocumentTypes on  t.DocumentTypeId equals tt.Id 
where tt.CreatedBy == 10
group t by t.DocumentTypeId into g
//let v = new {Version = g.Max( t => t.Version), TypeId =g.Key}
select new 
       {
           Key = g.Key, 
           Version = g.Max(t=>t.Version), 
           Text = t.Text //ERROR AT t.Text
       };

but it is giving me an error at following line:

Text = t.Text

The name 't' does not exist in the current context

I have tried g.Text also but it is not helping. Kindly help me to fix this query. I am trying this in LinqPad.

Answer 1

It seems that you need to retrieve a Document entity withing the same DocumentType which has the max value for the Version property. There is no need to group by ntext column.

After grouping you have groups of documents. The only thing left is to get one with the max Version value for each group. I’d order the group by this property in descending order, and get the first value:

from t in Documents
join tt in DocumentTypes on t.DocumentTypeId equals tt.Id
where tt.CreatedBy == 10
group t by t.DocumentTypeId into g
select g.OrderByDescending(t => t.Version).FirstOrDefault();

You could project the result Document entity into an anonymous type if you want.