... the MySQL reference manual?
... there used to be an O'Reilly book which tried to comapre the various servewr based SQL db's
... a ANSI standard SQL..... granted no server is 100% compatible.. but then again its would be better to write compatible SQL rather than vendor specific SQL, then you would need to know in which areas does MySQL (and its various flavours) differ from ANSI SQL
I don't think there is a quick and easy unified page that will tell you all that for all versions of MySQL