Pranay Rana: Get Last n Records using Linq to SQL

Saturday, May 26, 2012

Get Last n Records using Linq to SQL

The small post is about getting last n number of record(s) from the database table or from the collection using LINQ.

SQL
To get last n number of record(s) from table I do write the following query on my table records in T-SQL.
SELECT TOP n <fields> FROM Forms WHERE <field> = <data> 
ORDER BY <field> DESC
As you see in above query important thing is using order by with desc keyword means reversing the table records - (mostly we apply the order by desc on the primary key of the table).

LINQ
In LINQ we achieve the same thing with the help of OrderByDescending function and Take function.
var qry = db.ObjectCollection
                     .Where(m => m.<field> == data) 
                     .OrderByDescending(m => m.<field>) 
                     .Take(n); 
In above LINQ query same as sql need to apply the where condition first than make collection reverse using order by function and to get top record you just need to make user of Take function.

But to get the last record for the collection you make use of FirstOrDefault function as below
var qry = db.ObjectCollection
                     .Where(m => m.<field> == data) 
                     .OrderByDescending(m => m.<field>) 
                     .FirstOrDefault(); 

Read about the method use on MSDN

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