For an EXISTS subquery, the only thing that matters is whether it returns zero or more than zero rows. Therefore, we remove certain SQL features that won't affect that, among them the GROUP BY clauses. After we drop the groupClause, we'd better remove the RTE_GROUP RTE and clear the hasGroupRTE flag, as they depend on the groupClause. Failing to do so could result in a bogus RTE_GROUP entry in the parent query, leading to an assertion failure on the hasGroupRTE flag. Reported-by: David Rowley Author: Richard Guo Discussion: https://postgr.es/m/CAApHDvp2_yht8uPLyWO-kVGWZhYvx5zjGfSrg4fBQ9fsC13V0g@mail.gmail.com
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/devel/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/devel/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.