期中考试困难MySQL总结知识点ALL SOME(ANY)NULL带来的干扰 -> 将TF变成三值逻辑:有NULL值会影响ALL,如where gdp > all(select gdp from world where continent = 'Europe'),由于部分gdp为NULL,where gdp > NULL将不会成立。有NULL值会影响NOT IN,如WHER...
本文大多从Python代码阐释协程,如果你还不知道什么是协程,建议先阅读https://www.zhihu.com/question/294188439/answer/555273313;本文也算作观看Fear and Awaiting in Async: A Savage Journey to the Heart of the Coroutine Dream的笔记。从经典的网络socket...