To follow the examples, start TOPCAT and select TAP in the VO menu. Click the pin icon in the upper right corner of the dialog to keep the query window open even while the query is executing.
In TAP URL: at the bottom of the window, enter http://gaia.ari.uni-heidelberg.de/tap and click "Use Service".
At thebottom of the form, at Mode: check"Synchronous"and enter
SELECT TOP 1 1+1 AS result FROM gaiadr1.tgas_source
in the text box, then click"Ok". This should give you a table with a single 2 in it. If that hasn’t worked complain.Copying and Pasting from http://docs.g-vo.org/adql-gaia is legal.
Note that in the top part of the dialog there’s metadata on the tables exposed by the service (in particular, the names of the tables and the descriptions, units, etc., of the columns). Use that when you construct queries later.""