Mysql,MsAccess,Drivers.SQL syntax

I have been working with mysql for sometime now and have not really had to use anything else up to this point.
But recently Ive had to work with ms access. Ive found myself writing the same queries as I would in mysql for ms access but have found that some things are different. (Im writing these using perl and DBI).
So my question is, is it the drivers one uses which determine what the syntax of the sql can be given to the database or is it the database itself. Or as I suspect is it a mixture of the two ?

(mysql never complains about aggregate functions)

cheers