C# 查询表达式中的Ms access语法错误（缺少运算符）'；（数量*单价）扩展价格'；

每当我执行此查询时，都会出现以下错误-

查询表达式“”中的语法错误（缺少运算符）* 单价）扩展价格'

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请帮助使用AS-SQL别名用于为表或表中的列提供临时名称

OleDbConn.ole = "SELECT ProductCode, Description, Quantity, UnitPrice, (Quantity * UnitPrice) ExtendedPrice FROM SalesReturnItem sri INNER JOIN Product p ON p.ProductNo = sri.ProductID WHERE Sri.InvoiceNo = " 
+ invoiceNo + " ORDER BY Description ";

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仅显示SQL查询。下面是已解决的问题

OleDbConn.ole = "SELECT ProductCode, Description, Quantity, UnitPrice, (Quantity * UnitPrice) AS ExtendedPrice FROM SalesReturnItem sri INNER JOIN Product p ON p.ProductNo = sri.ProductID WHERE Sri.InvoiceNo = " 
+ invoiceNo + " ORDER BY Description ";