Using LINQ to find / remove duplicates

Question

I have a table containing a bunch of duplicates. These are exact duplicates, with the exception of the primary key column, which is an integer identifier column.

Using EF and LINQ, how to find duplicates and delete them, leaving only one copy.

I found duplicates and the amount of each of them using SQL and SSMS. I just don't know where to start LINQ.

Thanks!

Answer 1

On top of my head (untested):

var q = from r in Context.Table group r by new { FieldA = r.FieldA, FieldB = r.FieldB, // ... into g where g.Count() > 1 select g; foreach (var g in q) { var dupes = g.Skip(1).ToList(); foreach (var record in dupes) { Context.DeleteObject(record); } } Context.SaveChanges(); 

Answer 2

Set up @Craig Stuntz's answer with the “one liner” alternative:

 var duplicates = db.Table.GroupBy(a => new { a.FieldA, a.FieldB, ...}) .Where(a => a.Count() > 1) .SelectMany(a => a.ToList()); foreach (var d in duplicates) { db.DeleteObject(d); } db.SaveChanges();