SQL Server子查询填充DataSet时报500内部错误的解决办法

运行环境为Visual Studio 2010，数据库为SQL Server 2008。

执行下面SQL语句

SELECT SubsiteId, SubsiteTitle, count(CollectionID) CollectionNumber,count(LName) PlantNumber
   FROM (SELECT DISTINCT SubsiteId, SubsiteTitle, CollectionID, LName, CName
              FROM Cumplag_Garden_Plants where lname='Agave sisalana') 
group by SubsiteId, SubsiteTitle

在企业管理器中运行正常，可以查询到结果，但是放在程序中却始终提示500内部错误。以下是C#代码：

1 SqlConnection conn = new SqlConnection(strConn);
2 SqlCommand cmd = new SqlCommand(sql, conn);
3 conn.Open();
4 SqlDataAdapter sda = new SqlDataAdapter(cmd);
5 sda.Fill(ds, "ds");  //这里出错
6 conn.Close();

对代码try catch也捕获不到异常。

解决方法：只要将内部子查询添加一个别名即可。

SELECT  q.SubsiteId, q.SubsiteTitle, count(q.CollectionID) CollectionNumber,count(q.LName) PlantNumber
    FROM (SELECT DISTINCT SubsiteId, SubsiteTitle, CollectionID, LName, CName
             FROM Cumplag_Garden_Plants where lname='Agave sisalana') q
group by SubsiteId, SubsiteTitle