OleDbException：ORDER BY 子句中的语法错误

Posted 2023-05-06

【中文标题】OleDbException：ORDER BY 子句中的语法错误

【英文标题】：OleDbException: Syntax error in ORDER BY clause

【发布时间】：2012-09-12 17:20:58

【问题描述】：

我在测试如何通过选择所需列然后指定唯一 ID（即按主 ID、ID 排序的房间号）来获取最新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

任何帮助将不胜感激。谢谢！

【问题讨论】：

连接字符串是什么（提供者）？

【参考方案1】：

“LIMIT 1”子句是可疑的。建议修改查询以使用“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，此处使用硬返回包裹查询）。

【参考方案2】：

限制特定于 mysql。

对于 Access 或 SQL Server：

Select top 1 from ...
Order by ...

对于甲骨文：

Select *
from
(
    Select ...
    Order by ...
)
Where row_num = 1