How comparing database table rows using nested loop?

The code to do that would be something like this:

// insert code to create and fill a new DataRow, row2, of dataTable2

// now check whether there's already a similar row in dataTable1

bool hasSameRow = false;

foreach(DataRow row1 in dataTable1.Rows)
{
   bool hasSameColumns = true;

   for(int i = 0; i < row1.ItemArray.Length; i++)
   {    
      object item1 = row1.ItemArray[i];
      object item2 = row2.ItemArray[i];
      if(item1 == null && item2 == null)
         continue;
      else if(Convert.IsDBNull(item1) && Convert.IsDBNull(item2))
         continue;
      else if(item1.ToString() != item2.ToString())
      {
         hasSameColumns = false;
         break;
      }
   }

   if(hasSameColumns)
   {
       hasSameRow = true;
       break;
   }
}

if (!hasSameRow) dataTable2.Rows.Add(row2);  // OK to add it to dataTable2