explicitly document (non)proprietary SQL

[Yahoo Serious]

It would seem to be good to clearly and explicitly document what is standard
SQL and what is proprietary SQL. Proprietary being either MySQL, or someone
else's proprietary formats/commands, that are supported for compatibility.

At this moment it may be mentioned at the bottom of the explanation (an
example would be "13.3.2. USE Syntax"), but it would be nice to see it right
away, before reading the details and finding out at the last line.

Also, sometimes it does not seem to be mentioned explicitly. Where paragraph
13.3.2 is in a paragraph suggesting it is proprietary by the title starting
with MySQL: "13.3. MySQL Utility Statements". However, paragraph "13.4. MySQL
Transactional and Locking Statements" also suggests this, but "13.4.1. START
TRANSACTION, COMMIT, and ROLLBACK Syntax" does not mention anything about it
being proprietary.

Another point is, the proprietary formulation now is "The X statement is
provided for compatibility with Y.", which I think could be more explicit,
e.g. by adding something like "It is not standard SQL.".

Maybe it would be nice to always start a paragraph with:
SQL standard since: SQL <version> (<date>) (or "not yet")
MySQL since: MySQL <version> (<date>) (or "not yet", or "expected: ..." ?)
(or maybe in some cases: "MySQL until: MySQL <version> (<date>) ")

Thanks for your time,
Yahoo