Question

我想显示我想要选择的内容，但我只获得了一行。怎么解决它PLZ？我只获得了第一行数据，但是当我在第二轮中执行do时，它会跳过循环并结束该过程。

     ListView1.Items.Clear()


        SQLstring = "SELECT * From record WHERE member_code like '" & u1 & "' "


        SQLConnection.Open()
        SQLcommand = New MySqlCommand(SQLstring, SQLConnection)
        SQLdatareader = SQLcommand.ExecuteReader()

        Do While SQLdatareader.Read()
            a = (SQLdatareader.Item("book_code").ToString())
            b = (SQLdatareader.Item("member_code").ToString())
            c = (SQLdatareader.Item("book_status").ToString())
            d = (SQLdatareader.Item("Borrow_date").ToString())
            f = (SQLdatareader.Item("Due_date").ToString())


            SQLdatareader.Close()
            SQLcommand.Dispose()
            SQLConnection.Close()

            SQLstring = "SELECT * From book WHERE book_code like '" & a & "' "
            SQLConnection.Open()
            SQLcommand = New MySqlCommand(SQLstring, SQLConnection)
            SQLdatareader = SQLcommand.ExecuteReader()
            Do While SQLdatareader.Read()
                g = (SQLdatareader.Item("book_name").ToString())
                h = (SQLdatareader.Item("book_writer").ToString())
                i = (SQLdatareader.Item("book_year").ToString())
            Loop




            Dim SQLlist As ListViewItem = ListView1.Items.Add(g)
            SQLlist.SubItems.Add(h)
            SQLlist.SubItems.Add(i)
            SQLlist.SubItems.Add(d)
            SQLlist.SubItems.Add(f)
            If dtNow > f Then
                Dim fine_amount = f.Subtract(dtNow)
                SQLlist.SubItems.Add(fine_amount)

            Else
                SQLlist.SubItems.Add("0")
            End If


        Loop
        SQLdatareader.Close()
        SQLcommand.Dispose()
        SQLConnection.Close()

    End Sub

Answer 1

你可能希望在你的LIKE子句周围有一个％，所以：

SQLstring = "SELECT * From record WHERE member_code like '" & u1 & "%' "

这将返回所有具有以u1变量开头的member_code的行。如果你只有那里没有％的变量，它将只返回具有该member_code的行。

此外，与您的问题无关，但与Google“Bobby Tables”和“SQL Injection”无关。

无法在VB.net中查询多行MySQL数据库

1 个答案: