Learning DB2 without a local install

I don't think you can avoid a local install. I'm not aware of any online sites (e.g. SQLFiddle does not offer DB2).

In addition to the book you linked to, I can highly recommend the "DB2 SQL Cookbook" as well: http://mysite.verizon.net/Graeme_Birchall/id1.html

And don't forget the official manual: http://pic.dhe.ibm.com/infocenter/db2luw/v9r7/index.jsp

There is a free version of DB2, the Express-C Edition, which includes most of the features of the "real" DB2 servers.

It doesn't include some features, like label-based access controls or table partitioning; and it can only use up to 2GB of RAM and 2 processing cores. Have a look at this article to see what you may be missing out on from some of the "upper tier" editions of DB2.

Found one many years later in the UK.

https://dbfiddle.uk/?rdbms=db2_11.1

You can create tables there and run SQL validation against the Developer-C environment. However, despite high version 11.1, old ansi style is supported for stored code:

CREATE OR REPLACE procedure set_int
language sql
p1: begin
declare l_var integer;
   set l_var = 1;
end p1;