Answer 1

I found this article

Almost every join is an equijoin, because the condition for matching rows is based on the equality of two values—one from each of the tables being joined. So that's what makes it an equijoin: the ON condition is equality. This includes inner joins andall three types of outer joins

https://searchoracle.techtarget.com/answer/What-s-the-difference-between-an-SQL-inner-join-and-equijoin

https://stackoverflow.com/questions/5471063/is-inner-join-the-same-as-equi-join