OleDBCommand.ExecuteReader（）錯誤訪問2007

Question

我有這樣的代碼：

private void GenerarTicket(int prmFOLIO) 
     { 
      try 
      { 
       string Ticket = "Nombre de la tienda: UAMCAV\n" + 
        "RFC:XXXXXX\n" + 
        "------------------------------\n" + 
        "ARTICULO CANT PRECIO TOTAL\n" + 
        "------------------------------\n"; 
       string varSQL = "SELECT Detalle_Ventas.folio, Detalle_Ventas.id_articulo, Detalle_Ventas.cantidad, Detalle_Ventas.p_unitario, Detalle_Ventas.iva*Detalle_Ventas.p_unitario AS iva, Detalle_Ventas.cantidad*Detalle_Ventas.p_unitario AS total, articulos.desc_producto, Ventas.user_login, LEFT(Ventas.fecha,10) AS fecha " + " FROM Ventas INNER JOIN (articulos INNER JOIN Detalle_Ventas ON articulos.id_articulo=Detalle_Ventas.id_articulo) ON Ventas.folio=Detalle_Ventas.folio WHERE Ventas.folio=" + prmFOLIO + ""; 

       string DetalleTicket = ""; 
       double varGranTotal = 0; 
       OleDbConnection cnnTicket =new OleDbConnection(Clases.clsMain.CnnStr); 
       cnnTicket.Open(); 
       OleDbCommand cmdTicket =new OleDbCommand(varSQL, cnnTicket); 
       OleDbDataReader drTicket; 
       **drTicket = cmdTicket.ExecuteReader();** 
       while (drTicket.Read()) 
       { 
        DetalleTicket += 
         drTicket["desc_producto"].ToString() + " " + 
         drTicket["cantidad"].ToString() + " " + 
         String.Format("{0:C}", 
         drTicket["p_unitario"]) + " " + 
         String.Format("{0:C}", 
         drTicket["total"]) + "\n"; 
        varGranTotal += (double)drTicket["total"]; 
       } 
       DetalleTicket += 
        "------------------------------\n" + 
        "TOTAL: " + String.Format("{0:C}", 
        varGranTotal); 
       Ticket += DetalleTicket; 
       mPrintDocument _mPrintDocument = new mPrintDocument(Ticket); 
       _mPrintDocument.PrintPreview(); 
      } 
      catch (Exception ex) 
      { 
       MessageBox.Show(ex.Message); 
      } 
     } 

我修改了大膽的部分很多次，因爲總是有一個拋除怪我，像別名循環引用「desc_producto 「，我使用由我創建的.dll生成購物券，但無法解決此異常問題！你可以幫我嗎？順便說一下，這是數據庫中項目的名稱。

Answer 1

原因該異常的 =>循環引用由別名

別名，或標籤引起計算字段的，不能是相同的，以任何用於計算的字段名的領域。

將查詢更改爲下方。

string varSQL = 
       "**SELECT LEFT(desc_producto,10) as desc_product_o,**" + 
       " cantidad,p_unitario,total" + 
       " FROM Ventas WHERE Folio=" + prmFOLIO + ""; 

它會工作。

這是Microsoft支持link瞭解更多詳情。

更新

還需要內部更改代碼，而循環。

while (drTicket.Read()) 
{ 
    DetalleTicket += 
    drTicket["desc_product_o"].ToString() + " " + 
    drTicket["cantidad"].ToString() + " " + 
    String.Format("{0:C}", 
    drTicket["p_unitario"]) + " " + 
    String.Format("{0:C}", 
    drTicket["total"]) + "\n"; 
    varGranTotal += (double)drTicket["total"]; 
}