I've noticed that two GROUP BY ROLLUP queries behave differently in v17
compared to master and REL_18_STABLE. The issue can be reproduced by
following SQL:
``` SQL
CREATE TABLE t(id int);
INSERT INTO t SELECT generate_series(1, 3);
-- Query 1
SELECT DISTINCT 'XXX'
FROM t
GROUP BY ROLLUP (id, 1);
-- Query 2
SELECT 'XXX'
FROM t
GROUP BY ROLLUP(id)
HAVING NOT (NULL IS NULL);
```
After some git bisect work, I traced the root cause:
- The first issue was introduced by commit f5050f79 (Mark expressions
nullable by grouping sets).
- The second issue stems from commit 67a54b9e (Allow pushdown of HAVING
clauses with grouping sets).
Best regards,
Yuhang Qiu
