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在ASP.NET/C#中,我正在處理兩個表; Cart_Line項目和產品。我已經加入了這兩個表格,並創建了一個名爲「Extension」的新列,該列已將「Products.UnitPrice」乘以「Cart_LineItems.Quantity」。這是我的完整SQL查詢。如何從連接表中獲取創建的列的總和? SQL/C#
SELECT Cart_LineItems.ProductID, Products.Name, Products.UnitPrice,
Cart_LineItems.Quantity, Products.UnitPrice * Cart_LineItems.Quantity
AS Extension, Cart_LineItems.CartNumber
FROM (Cart_LineItems
INNER JOIN Products
ON Cart_LineItems.ProductID = Products.ProductID)
WHERE (Cart_LineItems.CartNumber = ?)
此查詢工作正常並填充的GridView我希望它的方式。如何獲得「擴展」列中字段的總和並將結果放在Web表單上的文本框中?
這是我在代碼背後使用的C#代碼。
String strAddSQL = "";
strAddSQL = "SELECT SUM(extension) as subtotal FROM (Cart_LineItems
INNER JOIN Products ON Cart_LineItems.ProductID = Products.ProductID)";
OleDbConnection myAddConn = new OleDbConnection();
OleDbDataReader myAddReader;
myAddConn.ConnectionString = this.SqlDataSource1.ConnectionString;
OleDbCommand myAddCmd = new OleDbCommand(strAddSQL, myAddConn);
myAddConn.Open();
myAddReader = myAddCmd.ExecuteReader();
while (myAddReader.Read())
{
txtSubTotal.Text = Convert.ToString(myAddReader["subtotal"]);
}
myAddReader.Close();
myAddConn.Close();
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