How to get difference between two DataTables

Question

I have these two datatables and I want to get the difference between them. Here is an example:

Table1
-------------------------
ID  |   Name 
---------------         


        

Answer 1

Try the below approach:

Initialization:

var columnId = new DataColumn("ID", typeof (int));
var columnName = new DataColumn("Name", typeof (string));
var table1 = new DataTable();
table1.Columns.AddRange(new[] {columnId, columnName});
table1.PrimaryKey = new[] {columnId};
table1.Rows.Add(1, "A");
table1.Rows.Add(2, "B");
table1.Rows.Add(3, "C");

var table2 = table1.Clone();
table2.Rows.Add(1, "A");
table2.Rows.Add(2, "B");
table2.Rows.Add(4, "D");

Solution:

var table3 = table1.Copy();
table3.AcceptChanges();
table3.Merge(table2);

var distinctRows = from row in table3.AsEnumerable()
                   where row.RowState != DataRowState.Modified
                   select row;

var distintTable = distinctRows.CopyToDataTable();

Above solution also works when there are new rows in table2 that were not present in table1.

distintTable constains C and D.

Answer 2

Try below, this is pretty basic. Merge two sets together, and get the difference. If the sets dont align up properly, then this will not work. Trying to Test the same

DataSet firstDsData = new DataSet();
DataSet secondDsData = new DataSet();
DataSet finalDsData = new DataSet();
DataSet DifferenceDataSet = new DataSet();
finalDsData.Merge(firstDsData);
finalDsData.AcceptChanges();
finalDsData.Merge(secondDsData);
DifferenceDataSet = finalDsData.GetChanges();

Answer 3

Try This ...

    public DataTable getDiffRecords(DataTable dtDataOne, DataTable dtDataTwo)
    {
        DataTable returnTable = new DataTable("returnTable");

        using (DataSet ds = new DataSet())
        {
            ds.Tables.AddRange(new DataTable[] { dtDataOne.Copy(), dtDataTwo.Copy() });

            DataColumn[] firstColumns = new DataColumn[ds.Tables[0].Columns.Count];
            for (int i = 0; i < firstColumns.Length; i++)
            {
                firstColumns[i] = ds.Tables[0].Columns[i];
            }

            DataColumn[] secondColumns = new DataColumn[ds.Tables[1].Columns.Count];
            for (int i = 0; i < secondColumns.Length; i++)
            {
                secondColumns[i] = ds.Tables[1].Columns[i];
            }

            DataRelation r1 = new DataRelation(string.Empty, firstColumns, secondColumns, false);
            ds.Relations.Add(r1);

            DataRelation r2 = new DataRelation(string.Empty, secondColumns, firstColumns, false);
            ds.Relations.Add(r2);

            for (int i = 0; i < dtDataOne.Columns.Count; i++)
            {
                returnTable.Columns.Add(dtDataOne.Columns[i].ColumnName, dtDataOne.Columns[i].DataType);
            }

            returnTable.BeginLoadData();
            foreach (DataRow parentrow in ds.Tables[0].Rows)
            {
                DataRow[] childrows = parentrow.GetChildRows(r1);
                if (childrows == null || childrows.Length == 0)
                    returnTable.LoadDataRow(parentrow.ItemArray, true);
            }

            foreach (DataRow parentrow in ds.Tables[1].Rows)
            {
                DataRow[] childrows = parentrow.GetChildRows(r2);
                if (childrows == null || childrows.Length == 0)
                    returnTable.LoadDataRow(parentrow.ItemArray, true);
            }
            returnTable.EndLoadData();
        }
        return returnTable;
    }

Answer 4

You can try the following code...

table1.AsEnumerable().Where(
    r =>!table2.AsEnumerable().Select(x=>x["ID"]).ToList().Contains(r["ID"])).ToList();

Answer 5

I will try to do it on a column level rather than a DataTable.

IEnumerable<int> id_table1 = table1.AsEnumerable().Select(val=> (int)val["ID"]);
IEnumerable<int> id_table2  = table2.AsEnumerable().Select(val=> (int)val["ID"]);
IEnumerable<int> id_notinTable1= id_table2.Except(id_table1);

Just adding a .Select() to your answer...

Answer 6

Try below, this is pretty basic. Merge two sets together, and get the difference. If the sets dont align up properly, then this will not work.

DataSet firstDsData = new DataSet();
DataSet secondDsData = new DataSet();
DataSet finalDsData = new DataSet();
DataSet DifferenceDataSet = new DataSet();
finalDsData.Merge(firstDsData);
finalDsData.AcceptChanges();
finalDsData.Merge(secondDsData);
DifferenceDataSet = finalDsData.GetChanges();