[KQP RBO] Add group by on expressions

[denis0x0D]

Changelog entry

Issue #27661

Changelog category

• Not for changelog (changelog entry is not required)

Description for reviewers

...

[github-actions]

🟢 2025-11-14 17:10:37 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-11-14 17:06:50 UTC Pre-commit check linux-x86_64-release-asan for d318e2f has started.
⚪ 2025-11-14 17:07:09 UTC Artifacts will be uploaded here
⚪ 2025-11-14 17:09:28 UTC ya make is running...
🟡 2025-11-14 19:15:39 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
15573	15007	0	230	305	31

🟢 2025-11-14 19:15:51 UTC Build successful.
🟢 2025-11-14 19:16:20 UTC ydbd size 3.9 GiB changed* by +61.6 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: 0459711	merge: d318e2f	diff	diff %
ydbd size	4 136 479 280 Bytes	4 136 542 400 Bytes	+61.6 KiB	+0.002%
ydbd stripped size	1 522 590 760 Bytes	1 522 618 312 Bytes	+26.9 KiB	+0.002%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

⚪ 2025-11-14 17:08:03 UTC Pre-commit check linux-x86_64-relwithdebinfo for d318e2f has started.
⚪ 2025-11-14 17:08:36 UTC Artifacts will be uploaded here
⚪ 2025-11-14 17:11:17 UTC ya make is running...
🟡 2025-11-14 18:39:52 UTC Some tests failed, follow the links below. Going to retry failed tests...

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
38905	36079	0	4	2796	26

⚪ 2025-11-14 18:40:04 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-11-14 18:51:53 UTC Tests successful.

Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
64 (only retried tests)	47	0	0	0	17

🟢 2025-11-14 18:52:00 UTC Build successful.
🟢 2025-11-14 18:52:19 UTC ydbd size 2.3 GiB changed* by +33.8 KiB, which is < 100.0 KiB vs main: OK

ydbd size dash	main: 0459711	merge: d318e2f	diff	diff %
ydbd size	2 479 861 256 Bytes	2 479 895 880 Bytes	+33.8 KiB	+0.001%
ydbd stripped size	520 820 720 Bytes	520 831 792 Bytes	+10.8 KiB	+0.002%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}