如何在一张表中按差异记录总计所有产品？

Question

我有下表，我想得到所有产品的总数：

prodcod | prodname | pricein | Qty | priceout

01      | Coca     | 12$     | 40  | 20$
02      | pepsi    | 6$      | 20  | 10$
03      | fanta    | 9$      | 50  | 15$
04      | M150     | 12$     | 10  | 20$

我想得到总数Qty = 120

Answer 1

SELECT SUM(Qty) AS TOTAL

FROM [TABLE_NAME]

Answer 2

SQL代码很简单：

SELECT SUM(Qty) FROM Products

从vb.net调用：

Dim Quantity As Integer
Using cn As New SqlConnection("connection string here"), _
      cmd As New SqlCommand("SELECT SUM(Qty) FROM Products", cn)

    cn.Open()
    Quantity = DirectCast(cmd.ExecuteScalar(), Integer)
End Using