I have a table, 'lasttraces', with the following fields.
Id, AccountId, Version, DownloadNo, Date
The data looks like this:
28092|15240000|1.0.7.1782|2009040004731|2009-01-20 13:10:22.000
28094|61615000|1.0.7.1782|2009040007696|2009-01-20 13:11:38.000
28095|95317000|1.0.7.1782|2009040007695|2009-01-20 13:10:18.000
28101|15240000|1.0.7.1782|2009040004740|2009-01-20 14:10:22.000
28103|61615000|1.0.7.1782|2009040007690|2009-01-20 14:11:38.000
28104|95317000|1.0.7.1782|2009040007710|2009-01-20 14:10:18.000
How can I, in LINQ to SQL, only get the last lasttrace of every AccountId (the one with the highest date)?
This question is related to
c#
.net
linq
linq-to-sql
If you just want the last date for each account, you'd use this:
var q = from n in table
group n by n.AccountId into g
select new {AccountId = g.Key, Date = g.Max(t=>t.Date)};
If you want the whole record:
var q = from n in table
group n by n.AccountId into g
select g.OrderByDescending(t=>t.Date).FirstOrDefault();
It could be something like:
var qry = from t in db.Lasttraces
group t by t.AccountId into g
orderby t.Date
select new { g.AccountId, Date = g.Max(e => e.Date) };
If you want the whole record,here is a lambda way:
var q = _context
.lasttraces
.GroupBy(s => s.AccountId)
.Select(s => s.OrderByDescending(x => x.Date).FirstOrDefault());
It could be something like:
var qry = from t in db.Lasttraces
group t by t.AccountId into g
orderby t.Date
select new { g.AccountId, Date = g.Max(e => e.Date) };
Go a simple way to do this :-
Created one class to hold following information
Go the list of sites stored on a ArrayList object. And executed following query to sort it in descending order by Level.
var query = from MyClass object in objCollection
orderby object.Level descending
select object
Once I got the collection sorted in descending order, I wrote following code to get the Object that comes as top row
MyClass topObject = query.FirstRow<MyClass>()
This worked like charm.
Here is a simple way to do it
var lastPlayerControlCommand = this.ObjectContext.PlayerControlCommands
.Where(c => c.PlayerID == player.ID)
.OrderByDescending(t=>t.CreationTime)
.FirstOrDefault();
Also have a look this great LINQ place - LINQ to SQL Samples
If you want the whole record,here is a lambda way:
var q = _context
.lasttraces
.GroupBy(s => s.AccountId)
.Select(s => s.OrderByDescending(x => x.Date).FirstOrDefault());
Here is a simple way to do it
var lastPlayerControlCommand = this.ObjectContext.PlayerControlCommands
.Where(c => c.PlayerID == player.ID)
.OrderByDescending(t=>t.CreationTime)
.FirstOrDefault();
Also have a look this great LINQ place - LINQ to SQL Samples
It could be something like:
var qry = from t in db.Lasttraces
group t by t.AccountId into g
orderby t.Date
select new { g.AccountId, Date = g.Max(e => e.Date) };
Go a simple way to do this :-
Created one class to hold following information
Go the list of sites stored on a ArrayList object. And executed following query to sort it in descending order by Level.
var query = from MyClass object in objCollection
orderby object.Level descending
select object
Once I got the collection sorted in descending order, I wrote following code to get the Object that comes as top row
MyClass topObject = query.FirstRow<MyClass>()
This worked like charm.
Source: Stackoverflow.com