mirror of
https://github.com/postgres/postgres.git
synced 2025-08-24 09:27:52 +03:00
18831346d4
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
<!-- doc/src/sgml/README.links -->
Linking within SGML documents can be confusing, so here is a summary:
Intra-document Linking
----------------------
<xref>
use to get chapter/section number from the title of the target
link, or xreflabel if defined at the target, or refentrytitle if target
is a refentry; has no close tag
http://www.oasis-open.org/docbook/documentation/reference/html/xref.html
<link>
use to supply text for the link, requires </link>
http://www.oasis-open.org/docbook/documentation/reference/html/link.html
linkend=
controls the target of the link/xref, required
endterm=
for <xref>, allows the text of the link/xref to be taken from a
different link target title
External Linking
----------------
<ulink>
like <link>, but uses a URL (not a document target); requires
</ulink>; if no text is specified, the URL appears as the link
text
http://www.oasis-open.org/docbook/documentation/reference/html/ulink.html
url=
used by <ulink> to specify the URL, required
Guidelines
----------
o If you want to supply text, use <link>, else <xref>
o Do not use text with <ulink> so the URL appears in printed output
o Specific nouns like GUC variables, SQL commands, and contrib modules
usually have xreflabels