集合

https://zhuanlan.zhihu.com/p/24338517

https://juejin.im/post/5c16041ff265da615b715c01

http://cloudgrassland.com/2016/05/hashtable%E6%BA%90%E7%A0%81%E5%89%96%E6%9E%90%EF%BC%88%E5%85%AD%EF%BC%89/

 

https://blog.csdn.net/MyHerux/article/details/79400962

 

最左匹配原则

https://segmentfault.com/a/1190000015416513

https://www.zhihu.com/question/36996520

https://glemontree.github.io/2017/12/10/[DB]%20mysql%E7%9A%84%E6%9C%80%E5%B7%A6%E5%89%8D%E7%BC%80%E5%8C%B9%E9%85%8D%E5%8E%9F%E5%88%99/