vb.net - OleDbException:ORDER BY 子句中的语法错误

Question

我在测试如何通过选择所需的列然后指定唯一 ID(即按主 ID、ID 排序的房间号)来获取最新的数据库条目时遇到此错误。

这是我的代码:

  Private Sub Form5_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Conn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=|DataDirectory|\patientinfo.accdb"
    Conn.Open()

  Dim statement As String = " SELECT room_number, patient_name,patient_age,date_confinement,type_sickness, type_fluid, bottle_used, drop_rate FROM tblPatientInfo WHERE room_number=1 ORDER BY ID DESC LIMIT 1"
  RetrieveInfos(statement)

  End Sub

  Public Sub RetrieveInfos(ByRef statement As String)
    Dim cmd As OleDbCommand = New OleDbCommand
    With cmd
        .CommandText = statement
        .CommandType = CommandType.Text
        .Connection = Conn
        .ExecuteNonQuery()


        '--read records in access database----------------
        Dim reader As OleDbDataReader = cmd.ExecuteReader
        While reader.Read
            lblName.Text = (reader.GetString(0))
            lblAge.Text = (reader.GetInt32(1).ToString)
            lblDate.Text = (reader.GetDateTime(2).ToString)
            lblSickness.Text = (reader.GetString(3))
            lblFluid.Text = (reader.GetString(4))
            lblBottle.Text = (reader.GetInt32(5).ToString)
            lbldrops.Text = (reader.GetInt32(6).ToString)

        End While
      reader.Close()

    End With
End Sub

如有任何帮助，我们将不胜感激。谢谢!

Answer 1

“LIMIT 1”条款值得怀疑。建议将查询修改为使用“SELECT TOP 1 .....”

Dim statement As String = " SELECT TOP 1 room_number, patient_name,patient_age,
                            date_confinement,type_sickness, type_fluid, bottle_used, drop_rate FROM 
                            tblPatientInfo WHERE room_number=1 ORDER BY ID DESC"

(为清楚起见，此处用硬返回包裹的查询)。