query should be:
select user_id,screen_name,password,last_visit,
second_to_last_visit from users where last_visit IS NULL;
Just an sql-ism
Mike
-----Original Message-----
From: Mark Stosberg [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, June 05, 2001 2:18 PM
To: [EMAIL PROTECTED]
Subject: Nulls appear not be respected
I'm using MySQL 3.23.32 and having trouble selecting values where a
column is null. Any help is appreciated. An example is below:
I need to get the rows where the last_visit column in the users table is
NULL.
I can see that there are some with this select statement:
(last_visit is a date field)
mysql> select user_id,screen_name,last_visit, second_to_last_visit from
users;
+---------+-----------------+------------+----------------------+
| user_id | screen_name | last_visit | second_to_last_visit |
+---------+-----------------+------------+----------------------+
| 1 | xxxxxx-fake | NULL | NULL |
| 2 | xxxxxxxxxx-fake | NULL | NULL |
| 3 | xxxxx-admin | 2001-05-24 | 2001-05-07 |
| 4 | xxxx-admin | 2001-05-08 | 2001-05-07 |
| 5 | xxxxx-admin | 2001-03-23 | 2001-03-21 |
However, if I ask for the rows where last_visit = NULL, it says there are
not any! :
mysql> select user_id,screen_name,password,last_visit,
second_to_last_visit from users where last_visit = NULL;
Empty set (0.00 sec)
Ideas?
Below is some more information about my environment.
Thanks!
-mark
>Release: mysql-3.22.32 (TCX binary)
>Environment:
<machine, os, target, libraries (multiple lines)>
System: SunOS sun01101.dn.net 5.6 Generic_105181-19 sun4u sparc
SUNW,UltraSPARC-IIi-Engine
Architecture: sun4
Some paths: /bin/perl /usr/ccs/bin/make /usr/local/bin/gmake
/usr/local/bin/gcc /usr/ucb/cc
GCC: Reading specs from
/usr/local/lib/gcc-lib/sparc-sun-solaris2.6/2.95.2/specs
gcc version 2.95.2 19991024 (release)
Compilation info: CC='gcc' CFLAGS='-O3 -fomit-frame-pointer' CXX='gcc'
CXXFLAGS='-O3 -fomit-
frame-pointer -felide-constructors -fno-exceptions -fno-rtti' LDFLAGS=''
Configure command: ./configure --prefix=/usr/local/mysql
'--with-comment=TCX binary' --with-low-memory --disable-shared
Perl: This is perl, version 5.005_03 built for sun4-solaris
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