Dim l As Date
        Dim datemas() As Date
        Dim x As Long
        x = 0
        SqlCom = New OleDbCommand("select Дата from Таблица1", Con)
        Con.Open()
        rs = SqlCom.ExecuteReader()
        ReDim datemas(1)
        If rs.HasRows Then
            While rs.Read()
                l = rs.GetDateTime(0).Date
                x = x + 1
                ReDim Preserve datemas(x)
                datemas(x) = l
            End While
        End If
        rs.Close()
        Con.Close()
        For x = 1 To UBound(datemas)
            TextBox2.Text = TextBox2.Text & x & ". " & datemas(x) & " - " & DateDiff("d", datemas(x), Now.Date) & vbCrLf
            SqlCom = New OleDbCommand("Update Таблица1 set Текущая = '" & DateDiff("d", datemas(x), Now.Date) & "' where Дата = '" & datemas(x) & "'", Con)
            DA = New OleDbDataAdapter(SqlCom)
        Next x

Update Таблица1 set Текущая = НужнаяФормула

 SqlCom = New OleDbCommand("select Дата from Таблица1", Con)

Sub CurrentDiff()

DT.Clear()
SqlCom = New OledbCommand("update Таблица1 set Текущая = '" & DateDiff("d", Дата, Now.Date) & "'", con)
DA = New OleDbDataAdapter(SqlCom)

SqlCom = New OledbCommand("update Таблица1 set Текущая = '" & DateDiff("d", Дата, Now.Date) & "'", con)

SqlCom = New OledbCommand("update [Таблица1] set [Текущая] = DateDiff(\"d\", [Дата], Date())" , con)

SqlCom = New OleDbCommand("update [Таблица1] set [Текущая] = DateDiff("d", [Дата], Now.Date)", Con)
        Con.Open()
        SqlCom.ExecuteNonQuery()
        DA = New OleDbDataAdapter(SqlCom)
        Con.Close()