DELETE Table1 WHERE ID in (SELECT ID FROM Table2)

 Conn.Execute "UPDATE Table1 SET Fld1 = true WHERE ID in (" & strToDeltete & ")", MyAffectedRecords

ADODB.Connection
Dim rs As ADODB.Recordset

Private Type TArr
   ID As Long
   CustomerID As String
   EmployeeID As Long
End Type
Dim Arr() As TArr

Private Sub Form_Load()
   Set Conn1 = New ADODB.Connection
   Conn1.CursorLocation = adUseClient
   Conn1.Open "Provider=SQLOLEDB.1;Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=Northwind"
   GetArray
   Dim i As Long
   Dim s As String
   For i =  0  To  10 
      s = s & Arr(i).ID & ", "
   Next
   MsgBox s
End Sub

Private Sub GetArray()
   Dim v As Variant
   Dim i As Long
   Dim n As Long
   Set rs = New ADODB.Recordset
   rs.Open "SELECT OrderID, CustomerID, EmployeeID FROM Orders", Conn1, adOpenForwardOnly, adLockReadOnly, adCmdText
   v = rs.GetRows
   n = UBound(v,  2 )
   ReDim Arr(n)
   For i =  0  To n
      With Arr(i)
         .ID = v( 0 , i)
         .CustomerID = v( 1 , i)
         .EmployeeID = v( 2 , i)
      End With
   Next
End Sub