postgresql <-> mysql commands

Has someone written a quickie document outlining some commands
to transistion from mysql -> postgresql ?

Simple little things like "SHOW TABLES" would be helpful.
I am not quite sure I fully understand it's authentication system,
but I can create a db and connect to it. I'd like to explore sql-ledger
a bit, therefore something like postgresql is required (I suspect it is
because of transactional support).

v/r
-Mike