I am using adodb and i want to view the selected field in two tables but only one table appears in datagrid and below are my codes.

Private Sub Form_Load()
Set cn = New adodb.Connection
cn.ConnectionString = "Provider=microsoft.jet.oledb.4.0;data source = " _
& App.Path & "\customers_infos.mdb; Persist security info= false"
cn.Open
cn.CursorLocation = adUseClient
Set rs = New adodb.Recordset
rs.Open "select * from tblcustomers_infos,tbltransactions,tblbilling", cn, adOpenKeyset, adLockOptimistic
Set DataGrid1.DataSource = rs

Why can you join the 2 tables and get the result set and bind to grid?