Add conv function

[hp77-creator]

Add new 'conv' function which provides support of converting numbers between '2-36' into each other,

sample usage include:

SELECT conv('10', 10, 2); -- 1010
SELECT conv('255', 10, 16); -- FF

Many of the decisions like invalid character handling, whitespace handling are inspired from MySQL implementation
and it closes #4633

Changelog category (leave one):

• New Feature

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

New conv function for converting numbers between bases, currently supports bases from 2-36

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

conv

Converts numbers between different number bases. The function takes a number in one base and converts it to another base, supporting bases from 2 to 36. This function is compatible with MySQL's CONV() function and handles partial invalid inputs by processing valid digits until the first invalid character.

Syntax

conv(number, from_base, to_base)

Arguments

• number — The number to convert. Can be a string or numeric type. Leading and trailing whitespace is automatically trimmed. String or Number
• from_base — The source base (2-36). Must be an integer. Integer
• to_base — The target base (2-36). Must be an integer. Integer

Implementation Details

• For bases higher than 10, letters A-Z (case insensitive) represent digits 10-35
• Negative numbers are handled using two's complement representation
• Invalid characters stop processing at the first invalid digit (left-to-right processing)
• Leading and trailing whitespace is automatically trimmed
• Returns empty string for invalid base ranges or completely invalid input

Returned value

• Returns the string representation of the number in the target base. String

Examples

Query:

SELECT conv('10', 10, 2);

Response:

┌─conv('10', 10, 2)─┐
│ 1010              │
└───────────────────┘

Query:

SELECT conv('FF', 16, 10);

Response:

┌─conv('FF', 16, 10)─┐
│ 255                │
└────────────────────┘

Query:

SELECT conv('123XYZ', 10, 16);

Response:

   ┌─conv('123XYZ', 10, 16)─┐
1. │ 7B                     │
   └────────────────────────┘

Query:

SELECT conv('-1', 10, 16);

Response:

┌─conv('-1', 10, 16)─┐
│ FFFFFFFFFFFFFFFF   │
└────────────────────┘

[clickhouse-gh]

Workflow [PR], commit [0b1e311]

Summary: ❌

job_name	test_name	status	info	comment
Stateless tests (amd_tsan, parallel, 2/2)		failure
	00156_max_execution_speed_sample_merge	FAIL
Stress test (amd_tsan)		failure
	Server died	FAIL
	Hung check failed, possible deadlock found (see hung_check.log)	FAIL
	Killed by signal (in clickhouse-server.log)	FAIL
	Fatal message in clickhouse-server.log (see fatal_messages.txt)	FAIL
	Killed by signal (output files)	FAIL
	Found signal in gdb.log	FAIL

[bharatnc]

I'll do one final round of review to ensure that everything looks ok and then we can merge.

[hp77-creator]

sure @bharatnc lmk if there's any changes needed.

[hp77-creator]

@bharatnc

03096_text_log_format_string_args_not_empty |

is failing now, I didn't do any change related to this? what should I do?

[bharatnc]

is failing now, I didn't do any change related to this? what should I do?

Yes, I'm not sure why it fails - I will check.

[hp77-creator]

currently these tests fail:
https://github.com/ClickHouse/ClickHouse/actions/runs/18041406470/job/51345778134?pr=83058

https://github.com/ClickHouse/ClickHouse/actions/runs/18041406470/job/51345778282?pr=83058

i will re-trigger the pipeline to see if these fail again, if they do, i will analyze the cause, from the first inference of the logs, it appears like one test failed because it was unable to load AWS credential, other failed on cleanup

so re-triggering these should work

[bharatnc]

The test failures not related, no need to re-trigger. Some small fixes suggested, otherwise looks good.

[bharatnc]

Mostly looks good, one comment needs addressing.

[bharatnc]

LGTM, can merge once builds finish.

[hp77-creator]

@bharatnc
No autogenerated function categories found in src/Functions/conv.cpp
No changes in docs for new feature and no autogenerated function categories found

I added in the comments, do I need to add somewhere else as well to get PR job pass?

[bharatnc]

I added in the comments, do I need to add somewhere else as well to get PR job pass?

I think it's happening because the String category is currently not autogenerated - only allowed ones are these.

Looks like you might need to add the docs for the new function here in the markdown for string-functions.

[bharatnc]

Btw, in future, please avoid rebase + force pushes to PR if you want to bring it up to date with master. Instead, do git fetch origin and git merge <origin/master> (adjust origin of master branch accordingly). Otherwise, we are unnecessarily rewriting entire commit history.

[hp77-creator]

I thought doing a merge would increase a commit, so I did rebase, I will use merge from now on

[hp77-creator]

@bharatnc since last two commits fast test is failing, it was passing before, I checked in some other PRs, it was failing in that as well:
https://github.com/ClickHouse/ClickHouse/actions/runs/18309278158/job/52134031576
https://github.com/ClickHouse/ClickHouse/actions/runs/18286111233/job/52132792584

one thing to note is that in all the PRs changes are related to some function code, do we need to increase some limit here?

[bharatnc]

@bharatnc since last two commits fast test is failing, it was passing before, I checked in some other PRs, it was failing in that as well:

02003_memory_limit_in_client doesn't look related, but I'll check.

[bharatnc]

Test failures not related. But just in case, let's wait for a fresh set of builds before merging.

[bharatnc]

Test failure not related:

• Stateless tests (amd_tsan, parallel, 2/2) - 00156_max_execution_speed_sample_merge

[hp77-creator]

Thanks a lot @bharatnc !!

[alexey-milovidov]

@bharatnc, please revert or fix: #90115

[alexey-milovidov]

Oh, looks like it's not yours...