These are the sources for a little course on ADQL.  Somewhat
regrettably, they are still written against a crazy, plain TeX-based
macro package, which you would need to install.
Clone it from <ssh://pubgit@sosa.tfiu.de/~/slide-tools>.  Apologies for
this.

You can find a formatted version of this at <http://docs.g-vo.org/adql>.

If you change the queries, see that you run make test afterwards; this
ought to catch typos, regressions, and similar mishaps.  See the
docstring in res/test_examples for how to customise testing.