Re: remaining sql/json patches

Himanshu,

On Mon, Mar 18, 2024 at 4:57 PM Himanshu Upadhyaya
<upadhyaya(dot)himanshu(at)gmail(dot)com> wrote:
> I have tested a nested case but why is the negative number allowed in subscript(NESTED '$.phones[-1]'COLUMNS), it should error out if the number is negative.
>
> ‘postgres[170683]=#’SELECT * FROM JSON_TABLE(jsonb '{
> ‘...>’ "id" : "0.234567897890",
> ‘...>’ "name" : { "first":"Johnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn", "last":"Doe" },
> ‘...>’ "phones" : [{"type":"home", "number":"555-3762"},
> ‘...>’ {"type":"work", "number":"555-7252", "test":123}]}',
> ‘...>’ '$'
> ‘...>’ COLUMNS(
> ‘...>’ id numeric(2,2) PATH 'lax $.id',
> ‘...>’ last_name varCHAR(10) PATH 'lax $.name.last', first_name VARCHAR(10) PATH 'lax $.name.first',
> ‘...>’ NESTED '$.phones[-1]'COLUMNS (
> ‘...>’ "type" VARCHAR(10),
> ‘...>’ "number" VARCHAR(10)
> ‘...>’ )
> ‘...>’ )
> ‘...>’ ) as t;
> id | last_name | first_name | type | number
> ------+-----------+------------+------+--------
> 0.23 | Doe | Johnnnnnnn | |
> (1 row)

You're not getting an error because the default mode of handling
structural errors in SQL/JSON path expressions is "lax". If you say
"strict" in the path string, you will get an error:

SELECT * FROM JSON_TABLE(jsonb '{
"id" : "0.234567897890",
"name" : {
"first":"Johnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn",
"last":"Doe" },
"phones" : [{"type":"home", "number":"555-3762"},
{"type":"work", "number":"555-7252", "test":123}]}',
'$'
COLUMNS(
id numeric(2,2) PATH 'lax $.id',
last_name varCHAR(10) PATH 'lax $.name.last',
first_name VARCHAR(10) PATH 'lax $.name.first',
NESTED 'strict $.phones[-1]'COLUMNS (
"type" VARCHAR(10),
"number" VARCHAR(10)
)
) error on error
) as t;
ERROR: jsonpath array subscript is out of bounds

--
Thanks, Amit Langote