使用SQLDataReader在C#中执行SQL Server查询时出现问题

Question

我试图在C#中执行查询,SqlDataReader但是我从数据库收到一条错误消息," ''附近的语法不正确'.".

我不确定我的SQL查询有什么问题.我可以在SQL Server Management Studio中完美地执行它.

try
{
   SqlConnection thisConnection = new SqlConnection();
   thisConnection.Open();
   SqlCommand thisCommand = thisConnection.CreateCommand();
   thisCommand.CommandText = "SELECT"
                +"db.name DBName,"
                +"tl.request_session_id,"
                +"wt.blocking_session_id,"
                +"OBJECT_NAME(p.OBJECT_ID) BlockedObjectName,"
                +"tl.resource_type,"
                +"h1.TEXT AS RequestingText,"
                +"h2.TEXT AS BlockingText,"
                +"tl.request_mode"
                +"FROM sys.dm_tran_locks AS tl"
                +"INNER JOIN sys.databases db ON db.database_id = tl.resource_database_id"
                +"INNER JOIN sys.dm_os_waiting_tasks AS wt ON tl.lock_owner_address = wt.resource_address"
                +"INNER JOIN sys.partitions AS p ON p.hobt_id = tl.resource_associated_entity_id"
                +"INNER JOIN sys.dm_exec_connections ec1 ON ec1.session_id = tl.request_session_id"
                +"INNER JOIN sys.dm_exec_connections ec2 ON ec2.session_id = wt.blocking_session_id"
                +"CROSS APPLY sys.dm_exec_sql_text(ec1.most_recent_sql_handle) AS h1"
                +"CROSS APPLY sys.dm_exec_sql_text(ec2.most_recent_sql_handle) AS h2";

   SqlDataReader thisReader = thisCommand.ExecuteReader();
   while (thisReader.Read())
   {
      Console.WriteLine("\t{0}\t{1}", thisReader["DBName"], thisReader["BlockedObjectName"]);
   }
   thisReader.Close();
   thisConnection.Close();
}
catch (SqlException e)
{
   Console.WriteLine(e.Message);
}

Answer 1

在连接的某些行的末尾需要空格:

例如:

            +"tl.request_mode"
            +"FROM sys.dm_tran_locks AS tl"

将创建SQL

 ...tl.request_modeFROM sys.dm_tran_locks AS tl...

将其更改为

            +"tl.request_mode " 
            +"FROM sys.dm_tran_locks AS tl"

还有一些其他行具有相同的问题.

这是一个很好的例子,说明为什么在测试动态构建的SQL字符串时实际打印出连接字符串非常重要,而不是仅仅粘贴代码并编辑引号和+符号.