Hi, Tom,
Thanks for your feedback! I'm a SQL newbie and the "implicit row constructor" syntax was an unwelcome surprise. I guess
painfuldebugging is one way to cement a concept...
Seems like this is a nothing-burger and probably has no place in the PostgreSql documentation. Although I feel like the
"principleof least surprise" has been violated here. :/
I appreciate the info!
---Jason
On Fri, Sep 5, 2025, at 2:17 PM, Tom Lane wrote:
> PG Doc comments form <noreply@postgresql.org> writes:
>> There is no mention of the difference in PostgreSql behavior if the select
>> list of columns is surrounded by parentheses or not.
>
> What you've written there is an implicit row constructor, that is
> "(a,b,...)" is taken as "ROW(a,b,...)". These are documented at [1],
> but it would be quite unwieldy to point out the possibility of this
> for every context in which it could be written.
>
> Personally I think implicit row constructors were one of the SQL
> committee's worst ideas, precisely because of the surprise factor.
> But it's in the standard so we're stuck with it.
>
> regards, tom lane
>
> [1]
> https://www.postgresql.org/docs/current/sql-expressions.html#SQL-SYNTAX-ROW-CONSTRUCTORS
On Fri, Sep 5, 2025, at 2:17 PM, Tom Lane wrote:
> PG Doc comments form <noreply@postgresql.org> writes:
>> There is no mention of the difference in PostgreSql behavior if the select
>> list of columns is surrounded by parentheses or not.
>
> What you've written there is an implicit row constructor, that is
> "(a,b,...)" is taken as "ROW(a,b,...)". These are documented at [1],
> but it would be quite unwieldy to point out the possibility of this
> for every context in which it could be written.
>
> Personally I think implicit row constructors were one of the SQL
> committee's worst ideas, precisely because of the surprise factor.
> But it's in the standard so we're stuck with it.
>
> regards, tom lane
>
> [1]
> https://www.postgresql.org/docs/current/sql-expressions.html#SQL-SYNTAX-ROW-CONSTRUCTORS
