From 026a8510a375e63f6a9a6f7f86bc28b69c9be8fa Mon Sep 17 00:00:00 2001
From: Bruce Momjian 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)
@@ -85,7 +85,8 @@
searches and case-insensitive regular expression searches? How do I
use an index for case-insensitive searches? PostgreSQL Data Base Management System Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
- Portions Copyright (c) 1994-6 Regents of the University of CaliforniaFrequently Asked Questions (FAQ) for PostgreSQL
-
4.9) In a query, how do I detect if a field
- is NULL?
+ 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
@@ -162,7 +163,7 @@
Permission to use, copy, modify, and distribute this software and its documentation for any purpose, without fee, and without a @@ -206,7 +207,7 @@
The primary anonymous ftp site for PostgreSQL is ftp://ftp.PostgreSQL.org/pub. + "ftp://ftp.PostgreSQL.org/pub/">ftp://ftp.PostgreSQL.org/pub/. For mirror sites, see our main web site.
A list of commercial support companies is available at http://techdocs.postg - resql.org/companies.php.
+ "http://techdocs.postgresql.org/companies.php"> + http://techdocs.postgresql.org/companies.php.Also check out our ftp site ftp://ftp.PostgreSQL.org/pub to + "ftp://ftp.PostgreSQL.org/pub/">ftp://ftp.PostgreSQL.org/pub/ to see if there is a more recent PostgreSQL version.
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.
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) ++
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