Vb 2008 "LIKE" not worling as I want it

I'm trying to learn VB 2008 after many years with VB6. I'm using Vb 2008 and not a more recent version as that's what I have. I'm using an Access db
I'm writing an name & address i/p routine. To be able to quickly select an existing entry, or to avoid duplication I use the LIKE query to select matching names as keystrokes are entered.
In VB6 this is what I've successfully used for years:-
mySQL = "SELECT ref,last_name,first_name,post_code,home_phone,addr1,addr2,addr3 FROM addr" & _
" WHERE last_name LIKE """ & saleaddr(0) & "*"""
In Vb 2008 I call this routine on keyup:-
Private Sub showAddr()
Dim mySQL As String
Dim i As Integer
ListBox1.Items.Clear()
mySQL = "SELECT aLastName FROM address WHERE aLastName LIKE '" & aLastName.Text & "%'"
da = New OleDb.OleDbDataAdapter(mySQL, con1)
da.Fill(ds, "Address")
For i = 0 To ds.Tables("Address").Rows.Count - 1
ListBox1.Items.Add(ds.Tables("Address").Rows(i).Item("aLastName"))
ds.Tables("Address").Rows(i).Item("aLastName") = ""
Next i
ds.Clear()
da.Fill(ds, "Address")
End Sub

This almost works but it finds duplicates of each applicable entry.
Could anyone help please?

To remove duplicates you must return distinct records, and one way for that is to use the GROUP BY clause.

Code:

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"SELECT aLastName FROM address WHERE aLastName LIKE '" & aLastName.Text & "%' GROUP BY aLastName"

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