excel - syncing two lists with VBA

Question

What is the best way to sync up two lists each of which may contain items not in the other? As shown the lists are not sorted - although if necessary sorting them first would not be an issue.

List 1 = a,b,c,e
List 2 = b,e,c,d

Using the lists above, I'm looking for a solution that will write out to a spreadsheet in two columns:

a
b  b
c  c
   d
e  e

Answer 1

Here are some notes on using a disconnected recordset.

Const adVarChar = 200  'the SQL datatype is varchar

'Create arrays fron the lists
asL1 = Split("a,b,c,", ",")
asL2 = Split("b,e,c,d", ",")

'Create a disconnected recordset
Set rs = CreateObject("ADODB.RECORDSET")
rs.Fields.append "Srt", adVarChar, 25
rs.Fields.append "L1", adVarChar, 25
rs.Fields.append "L2", adVarChar, 25

rs.CursorType = adOpenStatic
rs.Open

'Add list 1 to the recordset
For i = 0 To UBound(asL1)
    rs.AddNew Array("Srt", "L1"), Array(asL1(i), asL1(i))
    rs.Update
Next

'Add list 2
For i = 0 To UBound(asL2)
    rs.MoveFirst
    rs.Find "L1='" & asL2(i) & "'"

    If rs.EOF Then
        rs.AddNew Array("Srt", "L2"), Array(asL2(i), asL2(i))
    Else
        rs.Fields("L2") = asL2(i)
    End If

    rs.Update
Next

rs.Sort = "Srt"

'Add the data to the active sheet
Set wks = Application.ActiveWorkbook.ActiveSheet

rs.MoveFirst

intRow = 1
Do
    For intField = 1 To rs.Fields.Count - 1
        wks.Cells(intRow, intField + 1) = rs.Fields(intField).Value
    Next intField

    rs.MoveNext
    intRow = intRow + 1
Loop Until rs.EOF = True