Hello Vlad, The reason is: "If one or both arguments are NULL, the result of the comparison is NULL, except for the NULL-safe <=> equality comparison operator.
Thereore, "or NULL" in your select statement will always returned NULL. You can find all the rules for comparaison at URL: http://dev.mysql.com/doc/mysql/en/Comparison_Operators.html Regards, Bernard On Thursday 02 December 2004 06:48, Vlad Shalnev wrote: > Hi, All > > It's happen after upgrade from 3.23.46. > > Just look at this set of queries > > mysql> select 1 or null; > +-----------+ > > | 1 or null | > > +-----------+ > > | 1 | -> Ok > > +-----------+ > 1 row in set (0.00 sec) > > > mysql> create table a ( a int not null ); > Query OK, 0 rows affected (0.00 sec) > > mysql> select min( a ) is null from a; > +------------------+ > > | min( a ) is null | > > +------------------+ > > | 1 | -> Ok > > +------------------+ > 1 row in set (0.00 sec) > > > mysql> select min( a ) is null or null from a; > +--------------------------+ > > | min( a ) is null or null | > > +--------------------------+ > > | NULL | -> Why ??? > > +--------------------------+ > 1 row in set (0.00 sec) > > It is very important for me to solve this problem. Thanks for any help > > Info from mysqlbug script > > Server version 4.1.7 > Protocol version 10 > Connection Localhost via UNIX socket > UNIX socket /tmp/.mysql.sock > Uptime: 23 hours 43 min 34 sec > > Threads: 2 Questions: 53 Slow queries: 0 Opens: 20 Flush tables: 1 > Open tables: 6 Queries per second avg: 0.001 > > >C compiler: 2.95.3 > >C++ compiler: 2.95.3 > > > >Environment: > > <machine, os, target, libraries (multiple lines)> > System: SunOS asv 5.8 Generic_108529-23 i86pc i386 i86pc > Architecture: i86pc > > Some paths: /usr/local/bin/perl /usr/ccs/bin/make /opt/sfw/bin/gmake > /opt/sfw/bin/gcc /usr/local/bin/cc > GCC: Reading specs from > /opt/sfw/lib/gcc-lib/i386-pc-solaris2.8/2.95.3/specs gcc version 2.95.3 > 20010315 (release) > Compilation info: CC='gcc' CFLAGS='' CXX='g++' CXXFLAGS='' LDFLAGS='' > ASFLAGS='' > LIBC: > -rw-r--r-- 1 root bin 1608268 Jul 30 2003 /lib/libc.a > lrwxrwxrwx 1 root root 11 Mar 3 2004 /lib/libc.so -> > ./libc.so.1 -rwxr-xr-x 1 root bin 956112 Jul 30 2003 > /lib/libc.so.1 -rw-r--r-- 1 root bin 1608268 Jul 30 2003 > /usr/lib/libc.a lrwxrwxrwx 1 root root 11 Mar 3 2004 > /usr/lib/libc.so -> ./libc.so.1 > -rwxr-xr-x 1 root bin 956112 Jul 30 2003 /usr/lib/libc.so.1 > Configure command: ./configure '--prefix=/usr/local/mysql-4.1.7' > '--exec-prefix=/usr/local/mysql-4.1.7' > '--libexecdir=/usr/local/mysql-4.1.7/bin' '--localstatedir=/main/MysqlDB' > '--enable-thread-safe-client' > '--with-unix-socket-path=/tmp/.mysql.sock' '--with-mysqld-user=mysql' > '--without-debug' '--without-bench' '--with-charset=koi8r' > Perl: This is perl, version 5.005_03 built for i86pc-solaris > > -- > --------------------------------------------------------------------------- >----- Vlad A. Shalnev > E-mail: [EMAIL PROTECTED] > > "Gravity can't be blamed > for someone > falling in love" > > ( Albert Einstein ) -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
