Dim c, r, sFreeSp, strFree_space, strCS

' SQL Expression
strFree_space = "SELECT SUM(bytes / power(2,20)) FROM user_free_space WHERE tablespace_name=USER GROUP BY tablespace_name"
' Connection String
strCS = "Provider=MSDAORA.1;Password=PWD;User ID=MY_USER;Data Source=MY_SRV;Persist Security Info=True"

On Error Resume Next

Set c = CreateObject("ADODB.Connection")
c.ConnectionString = strCS
c.Open
If c.State =  1  Then ' adStateOpen = 1
    Set r = cnn.Execute(strFree_space)
    sFreeSp = r.Fields( 0 )
    c.Close
    MsgBox "Free_space " & (sFreeSp) & " Mb.", , "Готово"
Else
    MsgBox "Произошла какая-то неправильная ошибка",  16 , "Ахтунг!" 'vbCritical+vbOKOnly
End If