Mysql SQL，VB.Net |我可以使用什么查询来获取此值？

在上面的例子中，我希望它给我一个用户名的ID值

这是我试过的命令

Dim Query2 = String.Format("SELECT ID FROM account WHERE character = " & UsernameTextBox.Text & " ")
            Command = New MySqlCommand(Query2, mydbcon)
            Dim idtest = reader.Read.ToString
            MsgBox(idtest)

然而，它返回错误我做错了什么

以下是我正在编写的全部代码：

Try
        mydbcon.Open()
        Dim Query As String
        Query = String.Format("SELECT * FROM account WHERE username = '{0}' AND password = '{1}'", Me.UsernameTextBox.Text.Trim(), Me.PasswordTextBox.Text.Trim())
        Dim Command = New MySqlCommand(Query, mydbcon)
        reader = Command.ExecuteReader

        Dim count As Integer
        count = 0
        While reader.Read
            count = count + 1
        End While

        If count = 1 Then
            MessageBox.Show("Username and password are correct")
            Query = String.Format("SELECT username AS ID FROM account WHERE character = " & UsernameTextBox.Text & " ")
            Command = New MySqlCommand(Query, mydbcon)

            My.Settings.LoginID = reader.Read
            MsgBox(My.Settings.LoginID)
        ElseIf count > 1 Then
            MessageBox.Show("Username and password are duplicate")
        Else
            MessageBox.Show("Username and password are wrong")
        End If
        mydbcon.Close()
    Catch ex As MySqlException
        MessageBox.Show(ex.Message)
    Finally
        mydbcon.Dispose()
    End Try

使用ID作为别名，以便选择用户名作为您想要分配给它的任意名称：

---

它仍然返回false。它试图将其等同于什么？不要使用SQL。使用参数。不要将密码存储为明文。根据图像，如果这是Account表，则没有col命名字符…并且返回false到底是什么？该代码段不是函数，因此可以是函数。如果要执行第二个查询，您将得到另一个错误。

Dim Query2 = String.Format("SELECT username AS ID FROM account WHERE character = " & UsernameTextBox.Text & " ")