Re: Request for official clarification on SQL parameter parsing changes in PostgreSQL 15 and 16

On Thu, 2025-04-17 at 05:17 +0000, 王　博 wrote:
> We have encountered unexpected SQL parsing errors during application upgrades from
> PostgreSQL 14 to 15 and 16, related to the use of JDBC-style parameter
> placeholders (`?`) in our legacy applications.
>  
> Specifically:
>  
> 1. In PostgreSQL 15 and later:
>    The following SQL causes a syntax error unless a space is added after the `?`:
>      SELECT * FROM table WHERE a = ?AND b = 123;
>    → Adding a space (`? AND`) resolves the issue.
>    This did not cause an error in PostgreSQL 14.
>  
> 2. In PostgreSQL 16:
>    The following SQL causes a syntax error:
>      SELECT * FROM table WHERE a = ?ORDER BY b;
>    → This query runs in PostgreSQL 15, but causes an error in 16 unless a space is added after `?`.
>  
> We understand that this behavior may stem from changes to the parser to make it more
> strict and SQL-compliant. However, we were unable to find any explicit mention of these
> changes in the official release notes of PostgreSQL 15 or 16.
>  
> Our client is asking for official documentation or a statement confirming whether this
> behavior change was intentional and when it was introduced.
>  
> Could anyone kindly point us to:
> - Relevant release note sections, commits, or discussions on this change
> - Confirmation that these are intentional parser changes (and not regressions)

I'd say it is this change:

https://postgr.es/c/2549f0661bd28571d7200d6f82f752a7ee5d47e1

The mailing list discussion is here:

https://www.postgresql.org/message-id/flat/b239564c-cad0-b23e-c57e-166d883cb97d@enterprisedb.com

Yours,
Laurenz Albe