Obviously im thinking of this type of legal issue. https://www.theregister.co.uk/2017/06/09/intel_sends_arm_a_s... . Emulation is simply an implementation of API.
Google won out over Oracle in the end but it took a long time — from 2012 until 2016; four years of court cases — with some courts finding that API structures were copyrightable and others found that they were not, or that reimplementation was fair use. I guess we now have a precedent thanks to this but it could still be an issue? IANAL so I don’t know.
SQL is an international standard, that one needs to pay for, it isn't available for free.
Oracle already pays for SQL certifications, unlike Google does for Java.
James Gosling interview, at 57:42
https://www.youtube.com/watch?v=ZYw3X4RZv6Y
"unwilling to help us pays the bills", so nice for the Do No Evil company.
Oracle does pay for their ANSI/ISO SQL certifications.