From 026a8510a375e63f6a9a6f7f86bc28b69c9be8fa Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Fri, 25 Feb 2005 00:32:15 +0000
Subject: [PATCH] Fix HTML markup and add NULL sorting item to existing NULL
FAQ item.
Greg Sabino Mullan
---
doc/FAQ | 39 ++++++++++++++++++++++++++------------
doc/src/FAQ/FAQ.html | 45 +++++++++++++++++++++++++++++++-------------
2 files changed, 59 insertions(+), 25 deletions(-)
diff --git a/doc/FAQ b/doc/FAQ
index 9b985fc8329..1c63feda97d 100644
--- a/doc/FAQ
+++ b/doc/FAQ
@@ -1,7 +1,7 @@
Frequently Asked Questions (FAQ) for PostgreSQL
- Last updated: Mon Feb 14 23:35:09 EST 2005
+ Last updated: Thu Feb 24 19:32:04 EST 2005
Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
@@ -59,7 +59,8 @@
4.8) How do I perform regular expression searches and case-insensitive
regular expression searches? How do I use an index for
case-insensitive searches?
- 4.9) In a query, how do I detect if a field is NULL?
+ 4.9) In a query, how do I detect if a field is NULL? How can I sort on
+ whether a field is NULL or not?
4.10) What is the difference between the various character types?
4.11.1) How do I create a serial/auto-incrementing field?
4.11.2) How do I get the value of a SERIAL insert?
@@ -119,7 +120,8 @@
PostgreSQL Data Base Management System
Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
- Portions Copyright (c) 1994-6 Regents of the University of California
+ Portions Copyright (c) 1994-1996 Regents of the University of
+ California
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose, without fee, and without a written
@@ -160,7 +162,8 @@
1.4) Where can I get PostgreSQL?
The primary anonymous ftp site for PostgreSQL is
- ftp://ftp.PostgreSQL.org/pub. For mirror sites, see our main web site.
+ ftp://ftp.PostgreSQL.org/pub/. For mirror sites, see our main web
+ site.
1.5) Where can I get support?
@@ -177,14 +180,14 @@
EFNet.
A list of commercial support companies is available at
- http://techdocs.postg resql.org/companies.php.
+ http://techdocs.postgresql.org/companies.php.
1.6) How do I submit a bug report?
Visit the PostgreSQL bug form at
http://www.postgresql.org/support/submitbug.
- Also check out our ftp site ftp://ftp.PostgreSQL.org/pub to see if
+ Also check out our ftp site ftp://ftp.PostgreSQL.org/pub/ to see if
there is a more recent PostgreSQL version.
1.7) What is the latest release?
@@ -318,15 +321,15 @@
For Web integration, PHP (http://www.php.net) is an excellent
interface.
- For complex cases, many use the Perl and CGI.pm or mod_perl.
+ For complex cases, many use the Perl DBD::Pg with CGI.pm or mod_perl.
2.3) Does PostgreSQL have a graphical user interface?
Yes, there are several graphical interfaces to PostgreSQL available.
These include pgAdmin III (http://www.pgadmin.org, PgAccess
- http://www.pgaccess.org), RHDB Admin (http://sources.redhat.com/rhd b/
- ), TORA (http://www.globecom.net/tora/, partly commercial), and Rekall
- ( http://www.rekallrevealed.org/). There is also PhpPgAdmin (
+ http://www.pgaccess.org), RHDB Admin (http://sources.redhat.com/rhdb/
+ ), TORA ( http://www.globecom.net/tora/, partly commercial), and
+ Rekall ( http://www.rekallrevealed.org/). There is also PhpPgAdmin (
http://phppgadmin.sourceforge.net/ ), a web-based interface to
PostgreSQL.
@@ -634,10 +637,22 @@
expresssion index, it will be used:
CREATE INDEX tabindex ON tab (lower(col));
- 4.9) In a query, how do I detect if a field is NULL?
+ 4.9) In a query, how do I detect if a field is NULL? How can I sort on
+ whether a field is NULL or not?
You test the column with IS NULL and IS NOT NULL.
-
+ SELECT *
+ FROM tab
+ WHERE col IS NULL;
+
+ To sort by the NULLIS NULL
+ and IS NOT NULL modifiers in your WHERE clause. Things that are true
+ will sort higher than things that are false, so the following will put
+ NULL entries at the top of the resulting list:
+ SELECT *
+ FROM tab
+ ORDER BY (col IS NOT NULL)
+
4.10) What is the difference between the various character types?
Type Internal Name Notes
diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html
index dd6be2928e9..74a653e09da 100644
--- a/doc/src/FAQ/FAQ.html
+++ b/doc/src/FAQ/FAQ.html
@@ -10,7 +10,7 @@
alink="#0000ff">
<H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
- <P>Last updated: Mon Feb 14 23:35:09 EST 2005</P>
+ <P>Last updated: Thu Feb 24 19:32:04 EST 2005</P>
<P>Current maintainer: Bruce Momjian (<A href=
"mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)
@@ -85,7 +85,8 @@
searches and case-insensitive regular expression searches? How do I
use an index for case-insensitive searches?<BR>
<A href="#4.9">4.9</A>) In a query, how do I detect if a field
- is <SMALL>NULL</SMALL>?<BR>
+ is <SMALL>NULL</SMALL>? How can I sort on whether a field is <SMALL>
+ NULL</SMALL> or not?<BR>
<A href="#4.10">4.10</A>) What is the difference between the
various character types?<BR>
<A href="#4.11.1">4.11.1</A>) How do I create a
@@ -162,7 +163,7 @@
<P>PostgreSQL Data Base Management System</P>
<P>Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
- Portions Copyright (c) 1994-6 Regents of the University of California</P>
+ Portions Copyright (c) 1994-1996 Regents of the University of California</P>
<P>Permission to use, copy, modify, and distribute this software
and its documentation for any purpose, without fee, and without a
@@ -206,7 +207,7 @@
<H4><A name="1.4">1.4</A>) Where can I get PostgreSQL?</H4>
<P>The primary anonymous ftp site for PostgreSQL is <A href=
- "ftp://ftp.PostgreSQL.org/pub">ftp://ftp.PostgreSQL.org/pub</A>.
+ "ftp://ftp.PostgreSQL.org/pub/">ftp://ftp.PostgreSQL.org/pub/</A>.
For mirror sites, see our main web site.</P>
<H4><A name="1.5">1.5</A>) Where can I get support?</H4>
@@ -225,8 +226,8 @@
(<I>#postgresqlfr</I>). There is also a PostgreSQL channel on EFNet.
<P>A list of commercial support companies is available at <A href=
- "http://techdocs.postgresql.org/companies.php">http://techdocs.postg
- resql.org/companies.php</A>.</P>
+ "http://techdocs.postgresql.org/companies.php">
+ http://techdocs.postgresql.org/companies.php</A>.</P>
<H4><A name="1.6">1.6</A>) How do I submit a bug report?</H4>
@@ -235,7 +236,7 @@
http://www.postgresql.org/support/submitbug</A>.</P>
<P>Also check out our ftp site <A href=
- "ftp://ftp.PostgreSQL.org/pub">ftp://ftp.PostgreSQL.org/pub</A> to
+ "ftp://ftp.PostgreSQL.org/pub/">ftp://ftp.PostgreSQL.org/pub/</A> to
see if there is a more recent PostgreSQL version.</P>
<H4><A name="1.7">1.7</A>) What is the latest release?</H4>
@@ -411,7 +412,8 @@
href="http://www.php.net">http://www.php.net</A>) is an excellent
interface.</P>
- <P>For complex cases, many use the Perl and CGI.pm or mod_perl.</P>
+ <P>For complex cases, many use the Perl DBD::Pg with CGI.pm or
+ mod_perl.</P>
<H4><A name="2.3">2.3</A>) Does PostgreSQL have a graphical user
interface?</H4>
@@ -421,10 +423,9 @@
href="http://www.pgadmin.org">http://www.pgadmin.org</a>, PgAccess
<a href="http://www.pgaccess.org"> http://www.pgaccess.org</a>),
RHDB Admin (<a
- href="http://sources.redhat.com/rhdb/">http://sources.redhat.com/rhd
- b/ </a>), TORA (<a
- href="http://www.globecom.net/tora/">http://www.globecom.net/tora/</a>,
- partly commercial), and Rekall (<a
+ href="http://sources.redhat.com/rhdb/">http://sources.redhat.com/rhdb/
+ </a>), TORA (<a href="http://www.globecom.net/tora/">
+ http://www.globecom.net/tora/</a>, partly commercial), and Rekall (<a
href="http://www.rekallrevealed.org/">
http://www.rekallrevealed.org/</a>). There is also PhpPgAdmin (<a
href="http://phppgadmin.sourceforge.net/">
@@ -815,11 +816,29 @@ table?</TD><TD>unlimited</TD></TR>
</PRE>
<H4><A name="4.9">4.9</A>) In a query, how do I detect if a field
- is <SMALL>NULL</SMALL>?</H4>
+ is <SMALL>NULL</SMALL>? How can I sort on whether a field is <SMALL>
+ NULL</SMALL> or not?</H4>
<P>You test the column with <SMALL>IS NULL</SMALL> and <SMALL>IS
NOT NULL</SMALL>.</P>
+<PRE>
+ SELECT *
+ FROM tab
+ WHERE col IS NULL;
+</PRE>
+
+ <P>To sort by the <SMALL>NULL</SMALL status, use the <SMALL>IS NULL</SMALL>
+ and <SMALL>IS NOT NULL</SMALL> modifiers in your <SMALL>WHERE</SMALL> clause.
+ Things that are <I>true</I> will sort higher than things that are <I>false</I>,
+ so the following will put NULL entries at the top of the resulting list:</P>
+
+<PRE>
+ SELECT *
+ FROM tab
+ ORDER BY (col IS NOT NULL)
+</PRE>
+
<H4><A name="4.10">4.10</A>) What is the difference between the
various character types?</H4>
<BLOCKQUOTE>
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