Question

我正在创建类似工作的数据库。我是一名IT技术人员，我们有许多计算机可以进行重新映像。我们失去了很多，所以我决定建立一个“数据库”来记录所有内容。这些计算机带有故障单，我希望用户能够通过故障单号或序列号进行搜索。我的应用程序告诉我，当字段为空时，它告诉我何时没有结果，但我无法弄清楚如何使它如果它找到结果，我希望它显示文本框中该行的所有字段。如果它找到多个结果，我希望它显示最新的结果（行也包括它被引入的那一天）。这是我现在拥有的：

Private Sub btnSearch_Click(sender As Object, e As EventArgs) Handles btnSearch.Click
    Dim cmd As OleDbCommand

    If txtSearch.Text = "" Then
        MsgBox("No input", MsgBoxStyle.Exclamation, "Search")
        txtSearch.Focus()
    ElseIf InStr(txtSearch.Text, "'") Then
        MsgBox("Invalid character: '", MsgBoxStyle.Critical, "Search")
        txtSearch.Text = ""
        txtSearch.Focus()
    ElseIf rdoTicketNumber.Checked = True Then
        Dim sql = "select * from Tickets where Ticket_Number = '" & txtSearch.Text & "'"
        cmd = New OleDbCommand(sql, con)
        con.ConnectionString = ("provider=microsoft.jet.oledb.4.0;data source=../Database.mdb")
        con.Open()
        Dim dr As OleDbDataReader = cmd.ExecuteReader

        Try
            If dr.Read = False Then
                MsgBox("No Results", MsgBoxStyle.Information, "Search")
                txtSearch.Text = ""
                txtSearch.Focus()
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
        con.Close()
    ElseIf rdoSerialNumber.Checked = True Then
        Dim sql = "select * from Tickets where Asset_Serial = '" & txtSearch.Text & "'"
        cmd = New OleDbCommand(sql, con)
        con.ConnectionString = ("provider=microsoft.jet.oledb.4.0;data source=../Database.mdb")
        con.Open()
        Dim dr As OleDbDataReader = cmd.ExecuteReader

        Try
            If dr.Read = False Then
                MsgBox("No Results", MsgBoxStyle.Information, "Search")
                txtSearch.Text = ""
                txtSearch.Focus()
            End If
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try
        con.Close()
    End If
End Sub

感谢任何和所有帮助。提前谢谢！

Answer 1

如果您真的只想过滤查询字符串的结果：

Dim sql = "select * from Tickets where Asset_Serial = '" & txtSearch.Text & "'"

要过滤最近的一个，请将其更改为以下内容：

Dim sql = "select TOP(1) * from Tickets where Asset_Serial = '" & txtSearch.Text & "' ORDER BY <yourDateField> DESC"

您应该将<yourDateField>更改为Tickets表中该日期字段的名称，如果您只有一天的故障单，并且想要将结果过滤到该日期的最新日期我建议你这个：

Dim sql = "select TOP(1) * from Tickets where Asset_Serial = '" & txtSearch.Text & "' ORDER BY <yourDateField> DESC, <yourPKField> DESC"

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