On Thu, Jun 13, 2024 at 6:10 PM Chapman Flack <jcflack@acm.org> wrote:
On 06/13/24 16:43, David E. Wheeler wrote: > Paging Mr. Eisentraut!
I'm not Mr. Eisentraut, but I have at last talked my way into some access to the standard, so ...
Note 487 emphasizes that JSON path predicates "are not expressions; instead they form a separate language that can only be invoked within a <JSON filter expression>".
The only operators usable in a general expression (that is, a <JSON path wff> are binary + - and binary * / % and unary + - over a <JSON accessor expression>.
Inside a filter, you get to use a <JSON path predicate>. That's where you can use ! and && and ||. But ! can only be applied to a <JSON delimited predicate>: either a <JSON exists path predicate>, or any other <JSON path predicate> wrapped in parentheses.
On 06/13/24 11:32, David E. Wheeler wrote: > david=# select jsonb_path_query('true', '$ && $'); > david=# select jsonb_path_query('true', '$.boolean() && $.boolean()');
Those don't work because, as you recognized, they're not inside filters.
I'm content that the operators in the 'filter operators' table need to be within filter but then I cannot reconcile why this example worked: