Tom Lane a7eb633563 Fix mis-deparsing of ORDER BY lists when there is a name conflict.
If an ORDER BY item in SELECT is a bare identifier, the parser
first seeks it as an output column name of the SELECT (for SQL92
compatibility).  However, ruleutils.c is expecting the SQL99
interpretation where such a name is an input column name.  So it's
possible to produce an incorrect display of a view in the (admittedly
pretty ill-advised) case where some other column is renamed in the
SELECT output list to match an ORDER BY column.

This can be fixed by table-qualifying such names in the dumped
view text.  To avoid cluttering less-ill-advised queries, we'd
like to do so only when there's an actual name conflict.
That requires passing the current get_query_def call's resultDesc
parameter down to get_variable, so that it can determine what
the output column names are.  In hopes of reducing rather than
increasing notational clutter in ruleutils.c, I moved that value
into the deparse_context struct and removed it from the parameter
lists of get_query_def's other subroutines.

I made a few other cosmetic changes while at it:
* Likewise move the colNamesVisible parameter into deparse_context.
* Rename deparse_context's windowTList field to targetList,
since it's no longer used only in connection with WINDOW clauses.
* Replace the special_exprkind field with a bool inGroupBy,
since that was all it was being used for, and the apparent
flexibility of storing a ParseExprKind proved to be illusory.
(We need a separate varInOrderBy field to make this patch work.)
* Remove useless save/restore logic in get_select_query_def.

In principle, this bug is quite old.  However, it seems unreachable
before 1b4d280ea, because before that the presence of "new" and "old"
entries in a view's rangetable caused us to always table-qualify every
Var reference in dumped views.  Hence, back-patch to v16 where that
came in.

Per bug #18589 from Quynh Tran.

Discussion: https://postgr.es/m/18589-70091cb81db1a3f1@postgresql.org
2024-08-29 13:24:17 -04:00
2019-12-18 09:13:13 +01:00
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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/17/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/17/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/.

Description
Mirror of the official PostgreSQL GIT repository. Note that this is just a *mirror* - we don't work with pull requests on github. To contribute, please see https://wiki.postgresql.org/wiki/Submitting_a_Patch
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