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authorBruce Momjian <bruce@momjian.us>2005-02-25 00:32:15 +0000
committerBruce Momjian <bruce@momjian.us>2005-02-25 00:32:15 +0000
commit026a8510a375e63f6a9a6f7f86bc28b69c9be8fa (patch)
tree56ffa0e2816f95173ec256dca01966d74dfa1245 /doc/FAQ
parentd2557833e94323c36bb518446defba985e795643 (diff)
downloadpostgresql-026a8510a375e63f6a9a6f7f86bc28b69c9be8fa.tar.gz
postgresql-026a8510a375e63f6a9a6f7f86bc28b69c9be8fa.zip
Fix HTML markup and add NULL sorting item to existing NULL FAQ item.
Greg Sabino Mullan
Diffstat (limited to 'doc/FAQ')
-rw-r--r--doc/FAQ39
1 files changed, 27 insertions, 12 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