sql - 将参数添加到命令 ADO.NET

Question

我正在尝试使用以下代码从 db 中选择数据：

 getForecastsCommand.CommandText = @"SELECT TOP @Count * FROM Forecasts Order by [ForecastId] DESC";

   var countParam = getForecastsCommand.CreateParameter();
   countParam.ParameterName = "@Count";
   countParam.Value = count;
   countParam.DbType = DbType.Int32;
   getForecastsCommand.Parameters.Add(countParam);

但它不起作用：

Incorrect syntax near '@Count'.

为什么它不起作用？

Answer 1

请试试这个SELECT TOP (@Count) * FROM Forecasts Order by [ForecastId] DESC

请注意，@count 用括号括起来。

Answer 2

该语法看起来像 Microsoft Access 数据库。如果是，则不支持 TOP 参数。您将不得不构建字符串。

@"SELECT TOP " + Count + " * FROM Forecasts Order by [ForecastId] DESC";