我正在使用记录的id删除记录。当我执行此命令时，它将错误显示为“where子句中的未知列'id'”

mod_sql.conn2.Open()
sd_cmd2 = String.Format("DELETE FROM risk where `id`='{0}';", nd_index)
cmdd_delete2 = New MySqlCommand(sd_cmd2, mod_sql.conn2)
 cmdd_delete2.ExecuteNonQuery()
 mod_sqlconnect2.conn2.Close()

我试图将delete命令改为

sd_cmd2 = String.Format("DELETE FROM risk where `id`={0};", nd_index)

 sd_cmd2 = String.Format("DELETE FROM risk where id={0};", nd_index)

什么都没用。如果我复制同一个sql命令并在mysql工作台中尝试，记录就会被删除。