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Re: SQL/JSON: functions

Andrew Dunstan <andrew@dunslane.net>

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From: Andrew Dunstan <andrew@dunslane.net>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Greg Stark <stark@mit.edu>, Tom Lane <tgl@sss.pgh.pa.us>, Andres Freund <andres@anarazel.de>, Nikola Ivanov <kolioffx@gmail.com>, Himanshu Upadhyaya <upadhyaya.himanshu@gmail.com>, Nikita Glukhov <n.gluhov@postgrespro.ru>, pgsql-hackers@lists.postgresql.org, Dmitry Dolgov <9erthalion6@gmail.com>, Oleg Bartunov <obartunov@postgrespro.ru>, Erik Rijkers <er@xs4all.nl>
Date: 2022-04-08T12:15:08Z
Lists: pgsql-hackers 
On 4/8/22 08:02, Justin Pryzby wrote:
> On Thu, Mar 31, 2022 at 04:25:58PM -0400, Andrew Dunstan wrote:
>> No code chunks left, only a documentation patch which should land
> Documentation review for a6baa4bad.
>
>> Construct a JSON the provided strings:
> a JSON what ?
> *from* the provided strings ?
>
>> Construct a JSON from the provided values various types:
> should say "a JSON scalar" ?
> *of* various types ?
>
>> Construct a JSON object from the provided key/value pairs of various types:
> For comparison, that one looks ok.
>
> +      <function>JSON_EXISTS</function> function checks whether the provided
> +   <function>JSON_VALUE</function> function extracts a value from the provided
> +   <function>JSON_QUERY</function> function extracts an <acronym>SQL/JSON</acronym>
> +      <function>JSON_TABLE</function> function queries <acronym>JSON</acronym> data
> +     <function>JSON_TABLE</function> uses the
> +      <function>JSON_SERIALIZE</function> function transforms a SQL/JSON value
>
> I think all these should all begin with "THE >...< function ...", like the
> others do.
>
> +To use other types, you must create the <literal>CAST</literal> from <type>json</type> for this type.
> => create a cast from json to this type.
>
> +Values can be null, but not keys.
> I think it's clearer to say "..but keys cannot."
>
> +          For any scalar other than a number or a Boolean the text
>
> Boolean COMMA the text
>
> +     The path name must be unique and cannot coincide with column names.
> Maybe say "name must be unique and distinct from the column names."
>
> +      ... If you specify a <command>GROUP BY</command>
> +      or an <command>ORDER BY</command> clause, this function returns a separate JSON object
> +      for each table row.
>
> "for each table row" sounds inaccurate or imprecise.  The SELECT docs say this:
> | GROUP BY will condense into a single row all selected rows that share the same values for the grouped expressions
>
> BTW, the documentation references look a little like OIDs...
> Does someone already have an SNMP-based doc browser ?
> | For details, see Section 9.16.3.4.2.



Many thanks, useful.

I already had a couple of these items on my list but I ran out of time
before tiredness overcame me last night.

I'm planning on removing some of that stuff that generates the last
complaint if I can do it without too much violence.


cheers


andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. JSON_TABLE: Add support for NESTED paths and columns

  2. Add basic JSON_TABLE() functionality

  3. Add SQL/JSON query functions

  4. Add soft error handling to some expression nodes

  5. Adjust populate_record_field() to handle errors softly

  6. Refactor code used by jsonpath executor to fetch variables

  7. Add more SQL/JSON constructor functions

  8. SQL/JSON: support the IS JSON predicate

  9. SQL/JSON: add standard JSON constructor functions

  10. Improve readability of SQL/JSON documentation.

  11. Documentation for SQL/JSON features

  12. RETURNING clause for JSON() and JSON_SCALAR()

  13. SQL JSON functions

  14. SQL/JSON query functions

  15. IS JSON predicate

  16. SQL/JSON constructors

  17. Common SQL/JSON clauses

  18. Doc: remove obsolete entries in table of BRIN strategy numbers.

  19. Doc: standardize markup a bit more.

  20. Make pg_regress.c unset PGDATABASE during make installcheck.

  21. Fix handling of GENERATED columns in CREATE TABLE LIKE INCLUDING DEFAULTS.