select last(ts), a from test_last_pk.stb
explain select last(ts), a from test_last_pk.stb\G
select last(ts, a) from test_last_pk.stb
explain select last(ts, a) from test_last_pk.stb\G
select last(ts), a from test_last_pk.stb group by tbname order by tbname
explain select last(ts), a from test_last_pk.stb group by tbname\G
select last_row(ts), a from test_last_pk.stb group by tbname order by tbname
explain select last_row(ts), a from test_last_pk.stb group by tbname\G
select last_row(ts, a) from test_last_pk.stb group by tbname order by tbname
explain select last_row(ts, a) from test_last_pk.stb group by tbname\G
