1、什么是派生表derived关键字:子查询-->在From后where前的子查询例子:mysql>explainselect* from(select* fromt)awhereid=2;+---+---

Every derived table must he its own alias这句话的意思是说每个派生出来的表都必须有一个自己的别名一般在多表查询时,会出现此错误。因为,进行嵌

是Ja中的一个Derived类 base { override fun print() { print(x) } } class derived(b: base) :base by b实现继承的代替方式 fun main(args: array)

It was formerly derived by fermentation of carbohydrates but is now made synthetically by aldol condensation of acetaldehyde or by oxidation of petroleum gase