I'm testing complex SQLs on Postgres-XC 1.1.
And I found bad SQL that XC doesn't accept.
The SQL is from answer 2 of chapter 17 in SQL puzzle book by Joe Celko.
I simplified it for everyone's reproduction.
db=# CREATE TABLE t1(id INT, a INT);
CREATE TABLE
db=# CREATE TABLE t2(id INT, b INT);
CREATE TABLE
db=# SELECT DISTINCT t2.b FROM t1 JOIN t2 ON t1.id = t2.id GROUP BY b;
ERROR: ORDER/GROUP BY expression not found in targetlist
This SQL is accepted by PostgreSQL 9.2.4.