added hex function

[quantrpeter]

hex() function done

select hex(43981)

returns

0xabcd

[katzyn]

Thank you for your contribution!

Why do you need this function in H2 itself?

You can create a user-defined function instead:

CREATE ALIAS HEX FOR 'java.lang.Long.toHexString';

Built-in functions should be more advanced and configurable to be really useful for many users.

H2 actually already has a function for this purpose:

TO_CHAR(23423, 'FMXXXXXXXX')

Unfortunately, it only supports INTEGER values, but you can add support of BIGINT values to this function instead of introduction of another one.

[quantrpeter]

oh thanks, i have been asking in https://groups.google.com/g/h2-database/c/4tqipZkUzaE , seems we have to build a hotter forum.

If I write a java function and pack it into a jar, how can I expose it to H2 ? thanks

[katzyn]

If you use H2 embedded into your application, class with this function must be in classpath of your application.

If you have standalone H2 Server process, your function must be in its classpath. Client applications don't need it.