MySQL has a HUGE number of features. Some of these are not available on purpose, some of these are not available because of platform limitations and some of these are not available as a consequence of either of the above. I’m not sure if it would be possible to create an exhaustive list of everything that is not allowed or supported.
The temporary table restriction is a known limitation:
I suppose a good place to start would be the supported MySQL privileges list:
https://dev.mysql.com/doc/refman/5.7/en/privileges-provided.html
Of the privileges listed here, only the ALTER, CREATE, DELETE, DROP, INDEX, INSERT, SELECT, UPDATE and LOCK TABLES privileges are granted.
The point is that you can use MySQL as a quite dumb data store. Loading application/business logic into MySQL in any way is not possible.
If you want to change how data from the database is represented, do it in PHP. If you want to load intermediary data in memory for processing, do it in PHP. If you need some data change to affect other data as well, do it in PHP.
If you are looking for any particular features, I can look into whether it’s possible or not.