機房收費系統問題集錦（二）——組合查詢

在機房收費系統當中，有好幾個窗體設計到了組合查詢的問題，在這篇博客當中我就說一下組合查詢的事

首先，組合查詢的窗體如下所示：

爲簡單起見給圖中控件的命名ComboBox控件的命名左邊三列分別爲combo（1，2，3），中間的爲combo（4,5,6），右邊的爲（7,8）；文本框的命名就是Text（1,2,3）

查詢語句如下所示：

Private Sub cmdCheck_Click()    

    Dim ctrl As Control
    Dim mrc As ADODB.Recordset
    Dim txtSQL As String
    Dim Msgtext As String
    Dim i As Integer
    
    If Combo7.Text = "" Then   
    
       If Trim(Text1.Text) = "" Or Trim(Combo1.Text) = "" Or Trim(Combo4.Text) = "" Then
          MsgBox "請輸入完整的查詢條件", , "提示"
          Exit Sub
       Else
          txtSQL = "select * from Line_info where " & Trim(field(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'"
       End If
    Else
        
        If Combo8.Text = "" Then
           
           If Trim(Text2.Text) = "" Or Trim(Combo2.Text) = "" Or Trim(Combo5.Text) = "" Then
              MsgBox "請輸入完整的查詢條件", , "提示"
              Exit Sub
           Else
              txtSQL = "select * from Line_info where " & Trim(field(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'" & " " & Trim(field(Combo7.Text)) & " " & Trim(field(Combo2.Text)) & Trim(Combo5.Text) & "'" & Trim(Text2.Text) & "'"
           End If
        
        Else
           
           If Trim(Text3.Text) = "" Or Trim(Combo3.Text) = "" Or Trim(Combo6.Text) = "" Then
              MsgBox "請輸入完整的查詢條件", , "提示"
              Exit Sub
           Else
              txtSQL = "select * from Line_info where " & Trim(field(Combo1.Text)) & Trim(Combo4.Text) & "'" & Trim(Text1.Text) & "'" & " " & Trim(field(Combo7.Text)) & " " & Trim(field(Combo2.Text)) & Trim(Combo5.Text) & "'" & Trim(field(Text2.Text)) & "'" & " " & Trim(field(Combo8.Text)) & " " & Trim(field(Combo3.Text)) & Trim(Combo6.Text) & "'" & Trim(Text3.Text) & "'"
           End If
        
        End If
    
    End If
           
    Set mrc = ExecuteSQL(txtSQL, Msgtext)
    If mrc.EOF = True Then '檢查信息是否存在，如果不存在給出提示並清空所有文本框
        MsgBox "沒有查詢到結果，請檢查輸入信息！", vbOKOnly + vbExclamation, "提示"
        Call Cancel
        Exit Sub
    End If
    With MSHFlexGrid1
        .Rows = 1
        .TextMatrix(0, 0) = "卡號"
        .TextMatrix(0, 1) = "姓名"
        .TextMatrix(0, 2) = "上機日期"
        .TextMatrix(0, 3) = "上機時間"
        .TextMatrix(0, 4) = "下機日期"
        .TextMatrix(0, 5) = "下機時間"
        .TextMatrix(0, 6) = "消費金額"
        .TextMatrix(0, 7) = "餘額"
        .TextMatrix(0, 8) = "備註"
          
     Do While Not mrc.EOF
            .Rows = .Rows + 1
            .TextMatrix(.Rows - 1, 0) = mrc.Fields(1).Value & ""
            .TextMatrix(.Rows - 1, 1) = mrc!studentname
            .TextMatrix(.Rows - 1, 2) = Trim(mrc.Fields(6).Value & "")
            .TextMatrix(.Rows - 1, 3) = Trim(mrc.Fields(7).Value & "")
            .TextMatrix(.Rows - 1, 4) = Trim(mrc.Fields(8).Value & "")
            .TextMatrix(.Rows - 1, 5) = Trim(mrc.Fields(9).Value & "")
            .TextMatrix(.Rows - 1, 6) = Trim(mrc.Fields(10).Value & "")
            .TextMatrix(.Rows - 1, 7) = Trim(mrc.Fields(11).Value & "")
            .TextMatrix(.Rows - 1, 8) = Trim(mrc.Fields(12).Value & "")
            mrc.MoveNext
        Loop
    End With
    mrc.Close

End Sub

語句雖然是看似簡單，但是其中所含的信息無窮啊。在敲代碼的時候千萬不能忘記的空格的使用。

當然，大家也看到了在代碼部分有一個調用“call cancel”，大家可能會說這是什麼啊，沒見過啊！

這是我爲了方便書寫而定義的一個過程，代碼如下：

Public Function Cancel()
       Combo1.Text = ""
       Combo2.Text = ""
       Combo3.Text = ""
       Combo4.Text = ""
       Combo5.Text = ""
       Combo6.Text = ""
       Combo7.Text = ""
       Combo8.Text = ""
       Text1.Text = ""
       Text2.Text = ""
       Text3.Text = ""
    With MSHFlexGrid1
         .Rows = 2
         .CellAlignment = 4
         .TextMatrix(0, 0) = ""
         .TextMatrix(0, 1) = ""
         .TextMatrix(0, 2) = ""
         .TextMatrix(0, 3) = ""
         .TextMatrix(0, 4) = ""
         .TextMatrix(0, 5) = ""
         .TextMatrix(0, 6) = ""
         .TextMatrix(0, 7) = ""
         .TextMatrix(0, 8) = ""
         .TextMatrix(1, 0) = ""
         .TextMatrix(1, 1) = ""
         .TextMatrix(1, 2) = ""
         .TextMatrix(1, 3) = ""
         .TextMatrix(1, 4) = ""
         .TextMatrix(1, 5) = ""
         .TextMatrix(1, 6) = ""
         .TextMatrix(1, 7) = ""
         .TextMatrix(1, 8) = ""
    End With
End Function

這個過程主要是用於清空已填寫的數據的

還有一個要說明的就是field過程，這個過程是爲了方便我們查詢數據庫而存在的，定義過程如下：

Public Function field(comboX As String) As String
      Select Case comboX
            Case "卡號"
                field = "cardno"
            Case "姓名"
               field = "studentName"
            Case "上機日期"
               field = "ondate"
            Case "上機時間"
               field = "ontime"
            Case "下機日期"
               field = "offdate"
            Case "下機時間"
               field = "offtime"
            Case "消費金額"
               field = "consume"
            Case "餘額"
               field = "cash"
            Case "備註"
               field = "status"
            Case "與"
               field = "and"
            Case "或"
               field = "or"
       End Select
    
End Function

這篇文章的內容就這麼多了，就上圖的“導出爲Excel功能”請看《機房收費系統問題集錦（三）——導出爲Excel》