Re: SQL/JSON: functions

On 2021-01-20 03:49, Nikita Glukhov wrote:

> [0001-Add-common-SQL-JSON-clauses-v52.patch.gz]
> [0002-SQL-JSON-constructors-v52.patch.gz]
> [0003-IS-JSON-predicate-v52.patch.gz]
> [0004-SQL-JSON-query-functions-v52.patch.gz]
> [0005-SQL-JSON-functions-for-json-type-v52.patch.gz]
> [0006-GUC-sql_json-v52.patch.gz]

Hi,

I read through the file func.sgml (only that file) and put the 
errors/peculiarities in the attached diff.  (Small stuff; typos really)


Your patch includes a CREATE TABLE my_films + INSERT, to run the 
examples against.  I think this is a great idea and we should do it more 
often.

But, the table has a text-column to contain the subsequently inserted 
json values. The insert runs fine but it turns out that some later 
examples queries only run against a jsonb column.  So I propose to 
change:
   CREATE TABLE my_films (js text);
to:
   CREATE TABLE my_films (js jsonb);

This change is not yet included in the attached file.  An alternative 
would be to cast the text-column in the example queries as js::jsonb


I also noticed that some errors were different in the sgml file than 'in 
the event':


    SELECT JSON_QUERY(js, '$.favorites[*].kind' ERROR ON ERROR) FROM 
my_films_jsonb;
    (table 'my_films_jsonb' is the same as your 'my_films', but with js 
as a jsonb column)

manual says: "ERROR: more than one SQL/JSON item"
  in reality: "ERROR: JSON path expression in JSON_QUERY should return 
singleton item without wrapper"
         and:   "HINT: use WITH WRAPPER clause to wrap SQL/JSON item 
sequence into array"


Thanks,

Erik Rijkers

> 
> --
> Nikita Glukhov
> Postgres Professional: http://www.postgrespro.com
> The Russian Postgres Company