查找不同表的两列的总和，然后减去其总和

Question

您好我想打一个查询，先找到不同的表的两列的总和，然后减去其 例 它是一个Visual Basic程序

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'" 

Adodc2.RecordSource = large_tbl - sell_large 

请帮助 它显示了一个错误类型小姐比赛

Answer 1

两个变量large_tbl和sell_large都是字符串 - 只是文字尽可能VB关注。您需要连接到数据源（即Sql Server）并执行查询以获得数字结果。

你要求计算机做的是从“blah”中减去“blah”并执行它。

我想你指的是更多的东西一样：

Dim oCNX as ADODB.Connection 

:----Put code in here to open the connection to your database 

Dim resultA as ADODB.Recordset 
Dim resultB as ADODB.Recordset 

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'" 

Set resultA = oCNX.Execute(large_tbl) 
Set resultB = oCNX.Execute(sell_large) 

Do while not oRS.Eof() 

    Debug.Print "Result =" & (resultA(1).Value - resultB(1).Value) 

    oRS.MoveNext 
Loop 

或类似的东西。