Inventory query, return null access

I have the following structure:

Mycode:

PrivateSubCarregaEstoque()UsingconAsOleDbConnection=GetConnection()Trycon.Open()DimsqlAsString="SELECT IdProduto, Descricao, (SELECT SUM(Entradas.QtdEntrada) FROM Entradas WHERE Entradas.IdProduto = Produtos.IdProduto) - " & _
                                "(SELECT SUM(Saidas.QtdSaida) FROM Saidas WHERE Saidas.IdProduto = Produtos.IdProduto) AS Diferenca FROM Produtos"
            Dim cmd As OleDbCommand = New OleDbCommand(sql, con)
            Dim da As OleDbDataAdapter = New OleDbDataAdapter(cmd)
            Dim dt As DataTable = New DataTable
            da.Fill(dt)
            DataGridView1.DataSource = dt
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
        con.Close()
    End Using
End Sub

How to return the quantity of product 02, and had no outputs related to this?