Step 1: When you create a new connection, for example as shown here in Connect To hadoop article, you will get to Preview Screen.
Step 2: On preview screen, select the column you want to copy and click on down arrow.
Step 3: Click on "duplicate column" from the "Modify Column" section in the list and click on it.
Step 4: As and when you click on duplicate column, the selected column will be copied to a new column with name "Duplicate" which you can rename later on as desired.
