Tank,
Why would someone pay $10.00 for a document you can get better for free?
Why would they pay for the Microsoft JET details of SQL and not the MYSQL/PostgreSQL software that most use?
Here:
dev.mysql.com/doc/
You can choose to read the documentation online, or download your preferred version of the documentation. Your not forced to a PDF if you don't want them (you prefer html version which is really a better choice for technical documents, not PDF)
When you install mysql server you also get the full documentation installed also.
Perhaps no one looks in mysql/docs but they are there
Save your $10.00 for a more worthwhile expense, like food and water