Different results for QUOTE() with control characters between SQLite3 Fiddle and sqlite-jdbc

[dddddddcoconut]

Describe the bug
I noticed inconsistent behavior for the QUOTE() function when the input string contains control characters. The same query produces different results in SQLite3 Fiddle and sqlite-jdbc.

To Reproduce
Run the following SQL query:
SELECT QUOTE('L' || char(0x17) || 'A' || char(0x13) || '2');
In SQLite3 Fiddle and sqlite-jdbc, this query returns different outputs.

Expected behavior
I expected QUOTE() to produce identical output across both environments.
Is this difference expected, or could it indicate an inconsistency in how control characters are handled?

Logs
Result in sqlite-jdbc
'L A 2'

results in SQLite3 Fiddle
unistr('''L\u0017A\u00132''')

Environment (please complete the following information):
OS: Windows 11
CPU architecture: x86_64
sqlite-jdbc version: 3.51.2.0

Additional context
The difference seems to occur specifically when the input string contains control characters. It is unclear whether this is intended behavior or a potential inconsistency between environments.

[gotson]

If you are going to post screenshot of the SQLite forum, the least you can do is provide the link to the discussion.

[dddddddcoconut]

如果你要发SQLite论坛的截图，至少应该提供讨论链接。

Thanks for pointing that out! Here's the direct link to the discussion on the SQLite forum: https://sqlite.org/forum/forumpost/9c37fda250

[gotson]

Can you also advise what are those characters supposed to be ?

• char(0x17)
• char(0x13)

Is that Unicode ?

[dddddddcoconut]

Can you also advise what are those characters supposed to be ?

• char(0x17)
• char(0x13)

Is that Unicode ?

Yes, They are control characters.

char(0x17) and char(0x13) correspond to Unicode code points U+0017 and U+0013, which are part of the C0 control character range (U+0000–U+001F).

In this example they are simply used to construct a string containing control characters:

SELECT QUOTE('L' || char(0x17) || 'A' || char(0x13) || '2');

So the resulting string is effectively: L\u0017A\u00132.

[gotson]

Would probably need to investigate what happens in the SQLite C library instead of Sqlite Fiddle / CLI to understand what's going on.