mysql的基本语法及相应的练习,标对号的是没问题的,只有求交集和差集的时候执行不了,可能是mysql不支持intersect和minus ,背景黄色部分是进阶阶段-The basic syntax of mysql and the corresponding practice standard checkmark is no problem, only seeking the intersection and difference set when the execution can not,

MySQL的高级使用教程，非基础教程，而是进阶教程，会讲到MySQL的一些原理(A tutorial on advanced use of MySQL)