一、
http://bisqwit.iki.fi/source/sqlupdate.html
This program does not update a database. It only
produces update scripts (which show the differences).
二、
http://search.cpan.org/dist/MySQL-Diff/bin/mysqldiff
mysqldiff is a Perl script front-end to the CPAN module MySQL::Diff which compares the data structures (i.e. schema / table definitions) of two MySQL databases, and returns the differences as a sequence of MySQL commands suitable for piping into mysql which will transform the structure of the first database to be identical to that of the second (c.f. diff and patch).
Database structures can be compared whether they are files containing table definitions or existing databases, local or remote.