Question

我正在使用基于VB.NET和MySQL的基本银行系统，并且在交易历史记录中显示特定数据时遇到问题。问题是，我想显示从特定日期到特定日期（如边界或某物）发生的所有事务。这是我想要使用的代码行，但我无法使其工作：

Dim view As String =＆＃34;从tblhistory中选择*，其中accountnumber =＆＃39;＆＃34; ＆安培; txtAccount.Text＆amp; ＆＃34;＆＃39;和日期一样＆＃39;＆＃34; ＆安培; txtFrom.Text＆amp; ＆＃34;％＆＃39;或约会，如＆＃39;＆＃34; ＆安培; txtTo.Text＆amp; ＆＃34;＆＃39;＆＃34;

我想到的概念是，使用LIKE运算符，使用户输入的边界显示用户想要查看的唯一特定事务，而不是显示所有用户的事务并且无法查找那个特定的交易。

你们能帮我解决这个问题吗？非常感谢你。美好的一天。顺便提一下，这是完整的代码：

Public Class TransactionHistory
Public rights As String
Public log As String
Public accountnum As String
Private Sub btnProceed_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnProceed.Click
    lvHistory.Items.Clear()
    Dim con As New MySqlConnection("server = localhost ; uid = root ; database = dbbank")
    Dim view As String = "select * from tblhistory where accountnumber = '" & txtAccount.Text & "' and date like '" & txtFrom.Text & "%' or date like '" & txtTo.Text & "'"
    Dim cmd As New MySqlCommand(view, con)

    con.Open()
    Dim data As MySqlDataReader = cmd.ExecuteReader()

    While data.Read()
        Dim entries As ListViewItem
        entries = lvHistory.Items.Add(data(0))
        With entries
            .SubItems.Add(data(1))
            .SubItems.Add(data(2))
            .SubItems.Add(data(3))
            .SubItems.Add(data(4))
        End With
    End While

    If rights = "manager" Then
        Manager.Show()
        Me.Close()
    ElseIf rights = "teller" Then
        Teller.Show()
        Me.Close()
    End If
End Sub

Private Sub cmbType_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmbType.SelectedIndexChanged
    lvHistory.Items.Clear()
    Dim con As New MySqlConnection("server = localhost ; uid = root ; database = dbbank")
    Dim view As String = "select * from tblhistory where accountnumber = '" & txtAccount.Text & "' and transactiontype = '" & cmbType.SelectedItem & "'"
    Dim cmd As New MySqlCommand(view, con)

    con.Open()
    Dim data As MySqlDataReader = cmd.ExecuteReader()

    While data.Read()
        Dim entries As ListViewItem
        entries = lvHistory.Items.Add(data(0))
        With entries
            .SubItems.Add(data(1))
            .SubItems.Add(data(2))
            .SubItems.Add(data(3))
            .SubItems.Add(data(4))
        End With
    End While
End Sub

Private Sub btnCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCancel.Click
    Me.Close()
End Sub

Private Sub TransactionHistory_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    txtAccount.Text = accountnum
End Sub

结束班

Answer 1

＆＃39;或＆＃39;导致你的问题。它实际上就像要求这个帐户的所有内容以及像FROM＆＃34;这样的日期。并且还给我带来了像TO＆＃34;这样的日期。在日期条件周围添加括号可以解决这个问题。

我认为这可以解决一些问题：

NSManagedObjectContext *context = [self managedObjectContext];
NSManagedObject *object = [NSEntityDescription insertNewObjectForEntityForName:@"EY_Appliance" inManagedObjectContext:context];
[object setValue:self.applianceIdValue forKey:@"applianceId"];
[object setValue:self.applianceNameValue forKey:@"applianceName"];
[object setValue:self.wattsValue forKey:@"watts"];
[object setValue:self.amountPerWattsValue forKey:@"amountPerWatts"];
NSError *error = nil;
if (![context save:&error]) {
NSLog(@"Saving Failed with error %@", error);
}

但是，请记住，这只会查找特定日期的交易，而不是日期之间的交易。

也可以尝试

Dim view As String = "select * from tblhistory where accountnumber = '" 
& txtAccount.Text & "' and (date like '" & txtFrom.Text & "%' or date like '" & txtTo.Text & "')"

最后，使用参数。

使用两个文本框

1 个答案: