In this snippet I am going to discuss about how to get list of duplicate items for the collection that we do in sql.
For example I have to get list of the email id which is get entered in user table more than one time.
COUNT(email) AS NumOccurrences
GROUP BY email
HAVING ( COUNT(email) > 1 )
Linq query work same as on the set of collection and which make use of count
DataClassesDataContext db = new DataClassesDataContext();
var duplicates = db.Users
.GroupBy(i => i.emailid)
.Where(g => g.Count() > 1)
.Select(g => g.emailid);
foreach (var d in duplicates)
So by using above query you can easily achieve task of finding duplicate for your set of collection.