这是我想要的....

It is what I want....

Private Sub Command2_Click()
Dim con As New ADODB.Connection
con.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" _
     & App.Path & "\add_entry.mdb;Persist Security Info=False"

Dim rs As New ADODB.Recordset
Dim rs1 As New ADODB.Recordset
Dim result_hold As Integer

Dim large_tbl As String
Dim sell_large As String
large_tbl = "SELECT Sum(No_Of_Bottle) FROM add_cotton where Cateogry='Large'"
sell_large = "SELECT Sum(Quantity) FROM Sell_Detail where Cateogry='Large'"

rs.Open large_tbl, con, adOpenDynamic, adLockOptimistic
rs1.Open sell_large, con, adOpenDynamic, adLockOptimistic

result_hold = CInt(rs.Fields(0).Value) - CInt(rs1.Fields(0).Value)
Text1.Text = CStr(result_hold)
End Sub

'如果u需要回溯整个colum使用循环或其他...但有一件事是记住你两个来源
'从来没有使用单个网格附加...

'if u need to retreive whole colum use loop or etc.. but one thing is remember to you two sources 'never attach with single grid...