Re: SQL/JSON: FOR ORDINALITY bug

Op 04-05-2022 om 13:55 schreef Andrew Dunstan:
>
> On 2022-05-03 Tu 20:39, David G. Johnston wrote:
>> On Tue, May 3, 2022 at 5:27 PM Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:
>>
>>
>> On 2022-05-03 Tu 11:19, Erik Rijkers wrote:
>> > Hi
>> >
>> > I've copied some statements from the .pdf called:
>> > "TECHNICAL REPORT ISO/IEC TR 19075-6   First edition 2017-03
>> > Part SQL Notation support 6: (JSON) for JavaScript Object"
>> > (not available anymore although there should be a similar
>> replacement
>> > file)
>> >
>> > In that pdf I found the data and statement (called 'table 15' in the
>> > .pdf) as in the attached bash file.  But the result is different: as
>> > implemented by 15devel, the column rowseq is always 1.  It seems
>> to me
>> > that that is wrong; it should count 1, 2, 3 as indeed the
>> > example-result column in that pdf shows.
>> >
>> > What do you think?
>> >
>> >
>>
>> Possibly.
>>
>>
>> I don't see how rowseq can be anything but 1.  Each invocation of

After some further experimentation, I now think you must be right, David.

Also, looking at the DB2 docs:
https://www.ibm.com/docs/en/i/7.2?topic=data-using-json-table
(see especially under 'Handling nested information')

There, I gathered some example data + statements where one is the case
at hand. I also made them runnable under postgres (attached).

I thought that was an instructive example, with those 'outer_ordinality'
and 'inner_ordinality' columns.

Erik

>> json_table is given a single jsonb record via the lateral reference to
>> bookclub.jcol.  It produces one result, having a rowseq 1.  It does
>> this for all three outer lateral reference tuples and thus produces
>> three output rows each with one match numbered rowseq 1.
>>
>
> I imagine we could overcome that by stashing the sequence counter
> somewhere it would survive across calls. The question really is what is
> the right thing to do? I'm also a bit worried about how correct is
> ordinal numbering with nested paths, e.g. (from the regression tests):
>
>
> select
>     jt.*
> from
>     jsonb_table_test jtt,
>     json_table (
>         jtt.js,'strict $[*]' as p
>         columns (
>             n for ordinality,
>             a int path 'lax $.a' default -1 on empty,
>             nested path 'strict $.b[*]' as pb columns ( b int path '$' ),
>             nested path 'strict $.c[*]' as pc columns ( c int path '$' )
>         )
>     ) jt;
>  n | a  | b | c
> ---+----+---+----
>  1 |  1 |   |
>  2 |  2 | 1 |
>  2 |  2 | 2 |
>  2 |  2 | 3 |
>  2 |  2 |   | 10
>  2 |  2 |   |
>  2 |  2 |   | 20
>  3 |  3 | 1 |
>  3 |  3 | 2 |
>  4 | -1 | 1 |
>  4 | -1 | 2 |
>
>
> cheers
>
>
> andrew
>
> --
> Andrew Dunstan
> EDB: https://www.enterprisedb.com
>