On Fri, Jun 21, 2024 at 10:30:08AM +0800, jian he wrote:
> hi.
> -------------
> 9.16.2.1.1. Boolean Predicate Check Expressions
> As an extension to the SQL standard, a PostgreSQL path expression can
> be a Boolean predicate, whereas the SQL standard allows predicates
> only within filters. While SQL-standard path expressions return the
> relevant element(s) of the queried JSON value, predicate check
> expressions return the single three-valued result of the predicate:
> true, false, or unknown. For example, we could write this SQL-standard
> filter expression:
>
> -------------
> slight inconsistency, "SQL-standard" versus "SQL standard"
> "path expression can be a Boolean predicate", why capital "Boolean"?
I think "SQL-standard" is used with the dash above because it is an
adjective, and without the dash, it might be understood as "SQL
standard-path" vs. "SQL-standard path". There aren't clear rules on
when to add the dash, but when it can be misread, a dash is often added.
--
Bruce Momjian <bruce@momjian.us> https://momjian.us
EDB https://enterprisedb.com
When a patient asks the doctor, "Am I going to die?", he means
"Am I going to die soon?"
