GROUP BY is currently supported by simple_selection, the class used
when all selectors are simple. But when selectors are mixed, we use
selection_with_processing, which does not yet support GROUP BY. This
patch fixes that.
It also adapts one testcase in filtering_test to the new behavior of
simple_selector. The test currently expects the last value seen, but
simple_selector now outputs the first value seen.
(More details: the WHERE clause implicitly selects the columns it
references, and unit tests are forced to provide expected values for
these columns. The user-visible result is unchanged in the test;
users never see the WHERE column values due to filtering in
cql::transport, outside unit tests.)
Signed-off-by: Dejan Mircevski <dejan@scylladb.com>
f9b00a4318