Okay, It had been a year or two since I read up on MySQL so I went and read the page you suggested. And as far as I can see almost nothing has changed. In fact, things are worse than I remeber them (no subselects?). Here is a list of necessary features that MySQL still lacks (from the page you suggested):

• Foreign keys -- no referential integrity
• Constraints -- no database level issurance against bad data
• Triggers -- no cascading deletes, no database level auditing, or any of the other tricks triggers can do

Nice features that most Relational DBs have that MySQL doesn't

• Unions
• Views
• Cursors
• Subselects
• Stored Procedures

From the prouct page:

MySQL 4.1, the following development release

Internally, through a new .frm file format for table definitions, MySQL 4.0 lays the foundation for the new features of MySQL 4.1, such as nested subqueries, stored procedures, and foreign key integrity rules, which form the top of the wish list for many of our customers. Along with those, we will also include simpler additions, such as multi-table UPDATE statements.

After those additions, critics of MySQL have to be more imaginative than ever in pointing out deficiencies in the MySQL Database Management System. For long already known for its stability, speed, and ease of use, MySQL will then match the requirement checklist of very demanding buyers.

I agree with the last statment, except to point out that it doesn't take a whole lot of imaginiation to criticize them for lack of standard relational DB features.