Appending data rows


So i have two datatables, dt1 has about 300,000 rows, the other, dt2 about 100,000 rows;
I am trying to append dt2 to dt1, then perform a sort datatable on the combined datatable; then eliminate rows that have the similar values for 1st and 2nd Columns { dt1.Rows(0)(0) = dt1.Rows(1)(0) and dt1.Rows(0)(1) = dt.Rows(1)(1)}

append range is failing; i dont know if its as a result of the large dataset


would this activity help you?

I think join adds them side by side when there is a similar column.
I need something to append them above each other