MySql.Data.MySqlClient.MySqlException (0x80004005) [关闭]

Question

               try
                {

                   // Console.WriteLine("wtf");
                    con.ConnectionString = WebConfigurationManager.ConnectionStrings["dbconn"].ConnectionString;
                    cmd.Connection = con;
                    cmd.CommandType = System.Data.CommandType.Text;
                    con.Open();
                    cmd.CommandText = "select count(*) from hr WHERE emp_id=@1)";
                    cmd.Parameters.AddWithValue("@1", emp_id);

                   dr = cmd.ExecuteReader();
                   int count = 0;
                    while (dr.Read())
                     {
                         count = dr.GetInt32(0);
                     }
                     dr.Close();
                     cmd.Dispose();
                     cmd.Parameters.Clear();
                    if (count > 0)
                    {

                        cmd.CommandText = "DELETE FROM hr WHERE emp_id=@1')";
                        cmd.Parameters.AddWithValue("@1", emp_id);
                        cmd.ExecuteNonQuery();
                        res.Write("deleted");
                    }
                    else
                    {
                        res.Write("zero");
                    }
                    con.Close();

                }

dr = cmd.ExecuteReader(); 附近出现 sql 错误

错误信息：

 MySql.Data.MySqlClient.MySqlException (0x80004005): You have an error in your SQL
 syntax; check the manual that corresponds to your MySQL server version for the right
 syntax to use near ')' at line 1 at MySql.Data.MySqlClient.MySqlStream.ReadPacket() at 
MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId) at 
MySql.Data.MySqlClient.Driver.GetResult(Int32 statementId, Int32& affectedRows, Int64& 
insertedId) at MySql.Data.MySqlClient.Driver.NextResult(Int32 statementId, Boolean force)
 at MySql.Data.MySqlClient.MySqlDataReader.NextResult() at 
MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior) at 
MySql.Data.MySqlClient.MySqlCommand.ExecuteReader() at 
prod.Controller.HR.HRDel.ProcessRequest(HttpContext context

Answer 1

MySqlClient 需要 ? 参数 char 而不是 @

我也不确定1 是否是一个有效的参数名称。尝试使用?p_1

最后，正如 RhysW 所说，在你的 DELETE 语句中有一个额外的 ') 在你的 SELECT 语句中有一个 )