accept JSON_TABLE both as an unquoted table name and a table-valued function

[lovasoa]

This is an alternative to #1123

closes #1123
related to apache/datafusion#9122

see #1123 (comment)

This makes sqlparser accept both

select * from json_table 

And

select * from json_table(t, '$[*]' COLUMNS (id  INT PATH '$.id'))

in all dialects

[coveralls]

Pull Request Test Coverage Report for Build 7905402308

Details

• -1 of 11 (90.91%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.001%) to 87.687%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
tests/sqlparser_postgres.rs	6	7	85.71%

Totals
Change from base Build 7878309063:	0.001%
Covered Lines:	19655
Relevant Lines:	22415

---

💛 - Coveralls

[alamb]

Thank you @lovasoa -- I like this PR a lot

[alamb]

cc @viirya

[viirya]

Okay for me. Although I remember this is what @lovasoa is against to at the beginning...

EDIT: looks like it is not valid in supported engines as it is reserved keyword.

[lovasoa]

@viirya , this PR implements what I had suggested in apache/datafusion#9122 (comment)

[viirya]

@lovasoa I meant apache/datafusion#9122 (comment) (I think this is what your stand at the beginning).

[lovasoa]

Yes, my initial comment was about just ignoring the issue, which did not seem to satisfy everyone. This implements something even better that should make everyone happy.

[viirya]

Are you sure select * from json_table is valid in the engines which support json_table table function?

It is a reserved keyword in MySQL: https://dev.mysql.com/doc/refman/8.0/en/keywords.html#keywords-8-0-detailed-J

[lovasoa]

As stated above, this PR makes the parser accept BOTH the table identifier and the function in all dialects. I think this is a reasonable behavior.
Actual databases implement either one or the other.

[alamb]

Are you sure select * from json_table is valid in the engines which support json_table table function?

I tried running select * from json_table using dbfiddle: https://www.db-fiddle.com/f/ejJ4RKUDrtftShwtsLMCfA/1

It works in posgres and sqlite

mysql seems to require quoted identifiers:

[lovasoa]

@alamb : Yes, databases implement either the unquoted table reference syntax, or the table valued function syntax. But sqlparser now implements both.

[alamb]

Thanks again @lovasoa and @viirya

[lovasoa]

👍