Thread: A parsing question
Recently I was typing in a query in PG 10.4.
What I MEANT to type was: Where xyz >= 2400
What I actually typed was: Where xyz >- 2400
The latter was interpreted as 'where xyz > -2400', but I'm wondering if it shouldn't have thrown an error on an unrecognized operator '>-'
Thoughts?
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Mike Nolan
On Wed, Jun 3, 2020 at 3:41 PM Michael Nolan <htfoot@gmail.com> wrote:
Recently I was typing in a query in PG 10.4.What I MEANT to type was: Where xyz >= 2400What I actually typed was: Where xyz >- 2400The latter was interpreted as 'where xyz > -2400', but I'm wondering if it shouldn't have thrown an error on an unrecognized operator '>-'
From the syntax section of the documentation:
A multiple-character operator name cannot end in + or -, unless the name also contains at least one of these characters:
~ ! @ # % ^ & | ` ?
For example, @- is an allowed operator name, but *- is not. This restriction allows PostgreSQL to parse SQL-compliant queries without requiring spaces between tokens.
David J.
Michael Nolan <htfoot@gmail.com> writes:
> Recently I was typing in a query in PG 10.4.
> What I MEANT to type was: Where xyz >= 2400
> What I actually typed was: Where xyz >- 2400
> The latter was interpreted as 'where xyz > -2400', but I'm wondering if it
> shouldn't have thrown an error on an unrecognized operator '>-'
No, we do it that way intentionally, because the SQL standard requires us
to parse such cases in this way. The CREATE OPERATOR man page has some
details about what is and isn't a valid operator name ... and '>-' isn't
one. (The rules there probably look a bit bizarre, but the intention
is to ensure that operators found in the SQL spec can be parsed without
requiring spaces between them.)
regards, tom lane