EXPLAIN用法和结果分析

EXPLAIN
 select * from t_goods where 
  goods_id =( 
  select goods_id from t_goods where 
  goods_money="15")

如下链接查看：
http://note.youdao.com/noteshare?id=6d78d69affec1d2448ea185984154ca4&sub=FD217BF363D84D0A8E7CFB74CBFBD2EF

产生临时表的几种情况:
https://blog.csdn.net/weixin_43726822/article/details/89816185