mirror of
https://git.postgresql.org/git/postgresql.git
synced 2025-02-11 19:20:40 +08:00
b6423e92ab
The example of expansion of multiple views claimed that the resulting subquery nest would not get fully flattened because of an aggregate function. There's no aggregate in the example, though, only a user defined function confusingly named MIN(). In a modern server, the reason for the non-flattening is that MIN() is volatile, but I'm unsure whether that was true back when this text was written. Let's reduce the confusion level by using LEAST() instead (which we didn't have at the time this example was created). And then we can just say that the planner will flatten the sub-queries, so the rewrite system doesn't have to. Noted by Paul Jungwirth. This text is old enough to vote, so back-patch to all supported branches. Discussion: https://postgr.es/m/CA+renyXZFnmp9PcvX1EVR2dR=XG5e6E-AELr8AHCNZ8RYrpnPw@mail.gmail.com |
||
|---|---|---|
| config | ||
| contrib | ||
| doc | ||
| src | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| aclocal.m4 | ||
| configure | ||
| configure.in | ||
| COPYRIGHT | ||
| GNUmakefile.in | ||
| HISTORY | ||
| Makefile | ||
| README | ||
| README.git | ||
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. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.