SQLite

It has come to light that some legacy Android applications are coded
with queries that are logically equivalent to this:

<blockquote><verbatim>
CREATE TABLE t1(a,x);
CREATE TABLE t2(a,y);
SELECT t1.a AS a, x, y FROM t1, t2 GROUP BY a;
</verbatim></blockquote>

The original fix for this ticket (see check-in [f2d175f975cd]) caused such
queries to give an error:  "ambiguous column: a".  The query is indeed 
incorrect.  Nevertheless, we need to find a way to get SQLite to run and
return the correct result even for these incorrect, legacy queries.