以ms访问SQL设置最大ID条件 [英] Setting max ID criteria in ms access SQL

问题描述

This query does not run at the beginning. Could someone please help look at what is wrong?
This query does not run at the beginning. Could someone please help look at what is wrong?

What I have tried:

<pre>    strSQL1 = "SELECT * FROM PharmSales WHERE HospitalNo='" & Me.txtRegNo & "' And TDate = #" & Format(Me.txtTDate, "M\/dd\/yyyy") & "# AND SalesItem1 = '" & Me.txtSalesItem1 & "' And PharmSalesID=  (SELECT MAX(PharmSalesID) FROM PharmSales)"
            
        Set pr = db.OpenRecordset(strSQL1)
        
        With pr
        If Not .BOF And Not .EOF Then  'Ensure that the recordset contains records
        .MoveLast
        .MoveFirst
         If .Updatable Then  'To ensure record is not locked by another user
         .Edit  'Must start an update with the edit statement
         If IsNull(![TotalPaid]) = True And Me.txtGrand_TotalPay.Value >= Me.txtSalesAmt1.Value Then
         ![DispQty1] = Nz(![DispQty1] + Me.txtSalesQty1.Value, 0)
          .Update
               ElseIf IsNull(![TotalPaid]) = False And (Me.txtGrand_TotalPay.Value - Me.txtSalesAmt1.Value) >= (txtGrand_TotalFee - Me.txtGrand_TotalPay.Value + Me.txtSalesAmt1.Value) Then
         ![DispQty1] = Nz(![DispQty1] + Me.txtSalesQty1.Value, 0)
          .Update
        
         Else: MsgBox ("Insufficient balance!")
         End If
        End If
        End If
    
         pr.Close 
         Set pr = Nothing 
        Set db = Nothing
        End With
    
    End Sub

推荐答案

对于初学者，不要那样做！永远不要连接字符串来构建SQL命令。它让您对意外或故意的SQL注入攻击持开放态度，这可能会破坏您的整个数据库。请改用参数化查询。



其次，TextBox的默认ToString实现总是返回如下字符串：System.Windows.Forms.TextBox，Text：.. msgstr - 它不返回Text属性。

所以你的WHERE子句根本不匹配任何东西，所以不会返回任何行。

For starters, don't do it like that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.

Secondly, the default ToString implementation for a TextBox always returns a string like this: "System.Windows.Forms.TextBox, Text: ..." - it does not return the Text property.
So your WHERE clauses are unlikely to match anything at all, so no rows will be returned.

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