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我與下列的表MS Access和VB.net查詢錯誤
ID(integer)
mat_id(integer)
move_date(Date/Time)
rec_num (Short text)
Qty (number(double))
我已經做編程 的連接,並試圖查詢 代碼如下
Public Class ViewMatInfo
Dim ConStr As String = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\RMM\RMMDB.mdb;Persist Security Info=True"
Dim Conn As New OleDb.OleDbConnection(ConStr)
Dim ShowTable As New OleDb.OleDbCommand
Dim RAD As OleDb.OleDbDataReader
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
ShowTable.Connection = Conn
ShowTable.CommandType = CommandType.Text
ShowTable.CommandText = "SELECT Sum(qty) AS [totqty] FROM moves WHERE [mat_id] = " & MT_TEXT.SelectedValue.ToString & ""
Conn.Open()
RAD = ShowTable.ExecuteReader()
While RAD.Read
SUM_TEXT.Text = RAD.GetDouble("totqty")
End While
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
Try
Me.MovesTableAdapter.FillByMat(Me.RMMDS.moves, MT_TEXT.SelectedValue)
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Sub
End Class
當我運行應用程序並從「MT_TEXT」組合框中選擇材料時,然後單擊按鈕 ,數據網格視圖會充滿所有材料移動。 但SUM_TEXT文本框仍爲空。 並得到錯誤信息 「從字符串轉換‘totqty’到整數無效」
請有此問題的
的[文檔SELECT](https://msdn.microsoft.com/en-us/library/office/ff821148.aspx)不顯示任何分隔符排序別名 - 它是否工作,如果你使用'SELECT Sum(qty)AS totqty FROM'...?另外,我建議使用SQL參數,而不是將查詢值串聯到SQL字符串中。 –
哪一行會引發錯誤?這是一個嗎? SUM_TEXT.Text = RAD.GetDouble(「totqty」) – HarveyFrench
@Andrew。你是否修復了代碼?我給了一個修復的答案? – HarveyFrench