Feature/translate json functions #29306

[joelmandell]

Fixes #29306

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        Summary of the changes
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        Fixes #bugnumber

• Tests for the changes have been added (for bug fixes / features)
• Code follows the same patterns and style as existing code in this repo (Kinda... little bit different with unit-tests. But want to get your feedback if that's okay).

[roji]

Thanks for this PR - it's a good start, see comments below.

Note that there are some other JSON functions supported by SQL Server (ISJSON, JSON_ARRAY, JSON_OBJECT...). Ideally we'd have translations for all of them (and the relevant SQLite ones as well); of course you don't have to do that in this PR, but if you feel like working on those that would be great.

[joelmandell]

.

[joelmandell]

I made some changes now. And think I got them all covered. But little bit uncertain about the propagation of null.

[roji]

@joelmandell sorry, it's taking long for me to get around to this, here are some comments. Please rebase this PR on the latest main and check out any test failures after that.

[roji]

Any reason to add this rather than simply using JsonEntityBasic?

[joelmandell]

JsonEntityBasic has mappings of the columns to classes, and this works only for strings If I understand it correctly.

[celsowm]

json_value in differents rdbms:

mysql: https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=591207ceddca6fe4f11a3ad8589e7c5b
sqlserver: https://dbfiddle.uk/?rdbms=sqlserver_2017&fiddle=5c70245f5bb7c96d4adcc6b10ebed195
postgres: https://dbfiddle.uk/o46x7dyL
sqlite: https://www.db-fiddle.com/f/tMcVDVmjxb5wSjemg34dy8/2

[joelmandell]

@roji I know I was late to the party and missed to tag you in to this before feature freeze for 8.0... Do you have any advice or comments on how I can move forward with this one to perhaps get it ready for 9.0? I can as well look into the other requests for json functions if possible.

[roji]

@joelmandell sure thing - I'd also definitely like us to get this in for 9.0.

Here's my advice... Give us around a month, maybe a bit more to deal with the 8.0 release and the subsequent patching and other work - and then ping me here again. Assuming it's a good time to iterate on it, you can then rebase this PR on the latest main, and then we can get this to completed state and merge.

[Abdurahmon0412]

You must resolve conflict

[joelmandell]

Ping @roji. I do not know if it is to early to continue on this one now? :)

[roji]

@joelmandell I'm looking at this PR again (sorry for all the breaks and pauses). Since there was previously some problematic merge commit which messed up the entire history, I've squashed everything cleanly rebased on top of the latest main. In the interest of finally getting moving quickly and finally getting this merge, I'll do whatever fixup is still necessary and push commits on this PR.

[joelmandell]

@roji Sounds good. Thx