Re: PostgreSQL vs SQL/XML Standards

po 29. 10. 2018 v 11:05 odesílatel Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
napsal:

>
> (It would not be exactly overloading, because of the special sugared
>>> syntax known to the parser, but it could look like overloading, and be
>>> intuitive to the user.)
>>>
>>> If you have convenient access to Oracle to check compatibility, could you
>>> compare this query?
>>>
>>> SELECT * FROM XMLTABLE('.'
>>> PASSING '<sale hatsize="7" customer="alice" taxable="false"/>'
>>> COLUMNS
>>> a boolean PATH 'string("cat" < "dog")',
>>> b boolean PATH 'string("cat" > "dog")',
>>> c boolean PATH 'string(sale/@taxable = false())');
>>>
>>> (I suspect in Oracle it would also work without the string() wrappings,
>>> but just to make it easy, I think this way it will work in both Oracle
>>> and PG—that is, not error, though results may differ.)
>>>
>>
>>
>>
> I have a access to too old 11.2 Oracle. There I had to modify query
> because there is not boolean type. I replaced bool by int, but I got a error
> ORA-19224:XPTY-004 .. expected node()*, got xs:string - it doesn't work
> with/without string() wrappings.
>

The problem is in last line - the expression "sale/@taxable = false()" is
not valid on Oracle. Using string() wrapping is a issue, because it returns
"true", "false", but Oracle int doesn't accept it.

Pavel

> Regards
>
> Pavel Stehule
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