的MS Access VBA字符串连接会自动添加回车

Question

使用的MS Access 2016年，我复制我在查询设计器创建VBA查询，所以我可以动态改变基于窗体上的一些用户选择的WHERE子句。这个查询然后被设置为报告的记录源。

在窗体上，用户可以选择配置三个项目：1）日期，2）系统（所有系统或特定的一个），3）子系统（所有子系统或特定的一个）。在VBA中，我使用字符串连接组装查询语句，并根据所选选项设置WHERE子句。

该报告失败了，所以我开始调查。当我将字符串打印到即时窗口（debug.print）时，我可以很快看到错误。该字符串在大约1138个字符处得到相当长的时间（基于所选选项给出或取出）。字符1027附近VBA似乎自动插入回车。

这是正常的吗？有没有解决的办法？

这是我的代码：

'Procedure to execute report 
Private Sub cmdExecReport_Click() 
    On Error GoTo ErrHandler 

    Dim ssql As String 
    Dim ssql2 As String 
    Dim StartDate As Date 
    Dim System As Long 
    Dim SubSystem As Long 


    'Step 1: Acquire data from form 

    'Acquire start date 
    StartDate = Me.txtReportDate_Start.Value 
    'Acquire System 
    System = Me.cboSystem.Value 
    'Acquire SubSystem 
    SubSystem = Me.cboSubSystem.Value 


    'Step 2: Configure record source 

    'Assemble the record source string based on the selected items 
    ssql = "SELECT Reliability_MotorData.DateStamp, Config_BaseData_Motors.Service, Config_BaseData_Motors.SysCapacity_Pct AS [Total Capacity], " 
    ssql = ssql & "Reliability_MotorMasterList.EquipmentName AS Equipment, Config_BaseData_Motors.EquipSystem, Config_BaseData_Motors.EquipSubSystem, " 
    ssql = ssql & "Motor_GetSystemName([Config_BaseData_Motors].[EquipSystem]) AS System, Motor_GetSubSystemName([Config_BaseData_Motors].[EquipSubSystem]) AS [Sub System], " 
    ssql = ssql & "IIf(Motor_GetServiceStatus([Reliability_MotorData].[MotorID],[SelectDate])=-1," & """" & "OOS" & """" & ",IIf(Motor_GetServiceStatus([Reliability_MotorData].[MotorID]," 
    ssql = ssql & "[SelectDate])=0," & """" & "In Service" & """" & "," & """" & "Unknown" & """" & ")) AS [Service Mode], Motor_GetCurrentMotorCapacity([Reliability_MotorData].[MotorID],[SelectDate]) AS [Current Capacity] " 
    ssql = ssql & "FROM (Config_BaseData_Motors RIGHT JOIN Reliability_MotorMasterList ON Config_BaseData_Motors.MotorID = Reliability_MotorMasterList.MotorID) " 
    ssql = ssql & "INNER JOIN Reliability_MotorData ON Reliability_MotorMasterList.MotorID = Reliability_MotorData.MotorID " 

    'Configure the Where clause 
    ssql = ssql & "WHERE ((Reliability_MotorData.DateStamp = #" & StartDate & "#) " 

    'Configure the System list 
    ssql = ssql & "AND ((Config_BaseData_Motors.EquipSystem " 
    'Check the system selected 
    If System = -1 Then 'all systems 
     ssql = ssql & "Like " & """" & "*" & """" & ") " 
    Else 'specific one 
     ssql = ssql & "= " & System 
    End If 
    'Add closing paren 
    ssql = ssql & ") " 


    'Configure the SubSystem list 
    ssql = ssql & "AND ((Config_BaseData_Motors.EquipSubSystem " 
    'Check the subsystem selected 
    If SubSystem = -1 Then 'all subsystems 
     ssql = ssql & " Like " & """" & "*" & """" & ")" 
    Else 'specific one 
     ssql = ssql & "= " & SubSystem 
    End If 

    'Add closing paren & ; 
    ssql = ssql & ");" 

    Debug.Print ssql 

    'Step 3: Launch Report 
    ' DoCmd.OpenReport "Motor Capacity 4", acViewPreview, , , , ssql 

    Exit Sub 

ErrHandler: 
    'Write to event log 
    Call WriteWinEventLog(Error, Now() & " - " & "Execution error on form " & CurrentFormName & " in routine cmdExecReport_Click" & vbCrLf _ 
    & "Error Number: " & Err.Number & vbCrLf & "Source: " & Err.Source & vbCrLf & "Description: " & Err.Description) 

End Sub 

这里是打印的结果（线饲料添加的回车可见性）：

SELECT Reliability_MotorData.DateStamp，Config_BaseData_Motors.Service，Config_BaseData_Motors .SysCapacity_Pct AS [总容量]，Reliability_MotorMasterList.EquipmentName AS设备，Config_BaseData_Motors.EquipSystem，Config_BaseData_Motors.EquipSubSystem，Motor_GetSystemName（[Config_BaseData_Motors] [EquipSystem]）AS系统，Motor_GetSubSystemName（[Config_BaseData_Motors ] [EquipSubSystem]）AS [子系统]，IIF（Motor_GetServiceStatus（[Reliability_MotorData] [MotorID]，[SelectDate]。）= - 1， “OOS”，IIF（Motor_GetServiceStatus（[Reliability_MotorData] [MotorID]，[SelectDate ]）= 0， “以服务”， “未知”））AS [服务模式]，Motor_GetCurrentMotorCapacity（[Reliability_MotorData] [MotorID]，[SelectDate]）AS [电流容量] FROM（Config_BaseData_Motors RIGHT JOIN Reliability_MotorMasterList ON Config_BaseData_Motors.MotorID = Reliability_MotorMasterList.MotorID）INNER JOIN Reliability_MotorData ON Reliability_MotorMasterList.MotorID = Reliability_MotorData.MotorID WHERE（（Reliability_MotorData.DateStamp =＃7/10/2016年＃）

AND（（Config_BaseData_Motors.EquipSystem像 “”））AND（（ Config_BaseData_Motors.EquipSubSystem Like“”））;

我可以缩短我的查询了一下，并使其在这种情况下工作，但如果我想让他们选择多个系统或子系统呢？最终我会再次使用字符并遇到同样的问题。

有没有更好的方式使用级联实现我的目标是什么？我已经尝试过使用一个大的并置语句，并为WHERE子句使用第二个字符串变量，然后将它们一起打印出来debug.print ssql & ssql2。他们都产生相同的结果。

可替换地，如果存在方法的方式来动态地修改MS Access查询改变where子句;这可能是一个选择。

谢谢

Answer 1

最好的做法是不要在代码中构建SQL查询，无论如何。只需保存您构建的查询，然后使用参数化的querydef来调用它。例如。保存查询：

SELECT Reliability_MotorData.DateStamp, 
    Config_BaseData_Motors.Service, 
    Config_BaseData_Motors.SysCapacity_Pct AS [Total Capacity], 
    Reliability_MotorMasterList.EquipmentName AS Equipment, 
    Config_BaseData_Motors.EquipSystem, 
    Config_BaseData_Motors.EquipSubSystem, 
    Motor_GetSystemName([Config_BaseData_Motors].[EquipSystem]) AS System, 
    Motor_GetSubSystemName([Config_BaseData_Motors].[EquipSubSystem]) AS [Sub System], 
    IIf(Motor_GetServiceStatus([Reliability_MotorData].[MotorID], [SelectDate])=-1, 
     "OOS", 
     IIf(Motor_GetServiceStatus([Reliability_MotorData].[MotorID],[SelectDate])=0, 
     "In Service", 
     "Unknown")) AS [Service Mode], 
    Motor_GetCurrentMotorCapacity([Reliability_MotorData].[MotorID],[SelectDate]) AS [Current Capacity] 
FROM (Config_BaseData_Motors 
    RIGHT JOIN Reliability_MotorMasterList 
     ON Config_BaseData_Motors.MotorID = Reliability_MotorMasterList.MotorID) 
    INNER JOIN Reliability_MotorData 
     ON Reliability_MotorMasterList.MotorID = Reliability_MotorData.MotorID 
WHERE ((Reliability_MotorData.DateStamp = [SearchDate]) 
    AND ((Config_BaseData_Motors.EquipSystem Like [SearchSystem])) 
    AND ((Config_BaseData_Motors.EquipSubSystem Like [SearchSubSystem])); 

和查询它像：

Private Sub cmdExecReport_Click() 
    On Error GoTo ErrHandler 

    Dim qdf As QueryDef 
    Dim StartDate As Date 
    Dim System As Long 
    Dim SubSystem As Long 

    'Step 1: Acquire data from form 
    StartDate = Me.txtReportDate_Start.Value 'Acquire start date 
    System = Me.cboSystem.Value 'Acquire System 
    SubSystem = Me.cboSubSystem.Value 'Acquire SubSystem 

    'Step 2: Acquire QueryDef 
    Set qdf = CurrentDB.QueryDefs("qryMyParameterQuery") ' EDIT THIS 

    'Step 3: Substitute Parameters 
    'Substitute date 
    qdf.Parameters("SearchDate") = "#" & StartDate & "#" 

    'Substitute system 
    If System = -1 Then 
     qdf.Parameters("SearchSystem") = """*""" 
    Else 
     qdf.Parameters("SearchSystem") = """" & System & """" ' format as String 
    End If 

    'Substitute subsystem 
    If SubSystem = -1 Then 
     qdf.Parameters("SearchSubSystem") = """*""" 
    Else 
     qdf.Parameters("SearchSubSystem") = """" & SubSystem & """" ' format as String 
    End If 

    ' Step 4: Open report, recordset, etc. 
    ' Example: 
    'Dim rst As Recordset 
    'Set rst = qdf.OpenRecordset() 
    '... 

End Sub