Duplicate in Datatable

Question

How to Find Duplicate Recoreds in Colum 1 in a DataTable

Vinay Singh · Answer

hi try the below query SELECT name  email  COUNT (*) FROM users GROUP BY name  email HAVING COUNT (*) > 1 check detail http://stackoverflow.com/questions/2594829/finding-duplicate-values-in-a-sql-table http://stackoverflow.com/questions/2594829/finding-duplicate-values-in-a-sql-table http://stackoverflow.com/questions/4522431/find-duplicate-entries-in-a-column

Rajeesh Menoth · Answer

Hi Example : DataTable dt = new DataTable(); dt.Columns.Add(); dt.Columns.Add(); dt.Columns.Add(); dt.Rows.Add(1 Test1  Sample1 ); dt.Rows.Add(2 Test2  Sample2 ); dt.Rows.Add(3 Test3  Sample3 ); dt.Rows.Add(4 Test4  Sample4 ); dt.Rows.Add(5 Test5  Sample5 ); var duplicates = dt.AsEnumerable().GroupBy(r => r[0]).Where(gr => gr.Count() > 1).ToList(); Console.WriteLine( Duplicate found: {0}  duplicates.Any()); dt.Rows.Add(1 Test6  Sample6 ); // Duplicate on 1 dt.Rows.Add(1 Test6  Sample6 ); // Duplicate on 1 dt.Rows.Add(3 Test6  Sample6 ); // Duplicate on 3 dt.Rows.Add(5 Test6  Sample6 ); // Duplicate on 5 duplicates = dt.AsEnumerable().GroupBy(r => r[0]).Where(gr => gr.Count() > 1).ToList(); if (duplicates.Any()) Console.WriteLine( Duplicate found for Classes: {0}  String.Join(    duplicates.Select(dupl => dupl.Key))); Console.ReadLine(); Reference : http://stackoverflow.com/questions/8939516/how-to-find-duplicate-record-using-linq-from-datatable