There are two good articles on the web that discuss this issue, but none of them is perfect for me. So I tried to add my stuff here.
The first is about installing sqlplus: http://www.danilovizzarro.it/2008/07/how-to-install-sqlplus-and-the-oracle-client-v102-on-a-mac-os-x-leopard-1054/
The second is about installing DBD::Oracle: http://blacka.com/david/2008/11/12/how-to-install-dbdoracle-on-mac-os-x/

To install sqlplus, you need download instantclient form oracle site, the following (64-bit) packages:

To install DBD::Oracle, you need one more package:

Once you download and unzip them, all the files will go to a directory called instantclient_10_2. Move this folder to something like /opt/oracle


$ sudo mv instantclient_10_2 /opt/oracle


You should set unix environment variable like the following:

DYLD_LIBRARY_PATH="/opt/oracle/instantclient_10_2"
export DYLD_LIBRARY_PATH
TNS_ADMIN="/opt/oracle/tns"
export TNS_ADMIN
ORACLE_HOME="/opt/oracle/instantclient_10_2"
export ORACLE_HOME


To connect to the an Oracle via sqlplus you can run the following command:

# sqlplus DB_USER/DB_PASS@//DB_HOST:DB_PORT/DB_SID


To install DBD::Oracle, you will need to download perl DBD package from CPAN, I chose version 1.32.

After you download the package, unzip it to ~/Download/DBD-Oracle-1.32, make sure you have set ORACLE_HOME and DYLD_LIBRARY_PATH correctly.
You need to set some soft link in $ORACLE_HOME (This is the key step most readme files failed to mention.)


$ cd /opt/oracle/instantclient_10_2/
$ sudo ln -s /opt/oracle/instantclient_10_2/ lib
$ sudo ln -s libclntsh.dylib.10.1 libclntsh.dylib
$ ls -l

lrwxr-xr-x 1 root admin 31 Oct 19 16:36 lib -> /opt/oracle/instantclient_10_2/
lrwxr-xr-x 1 root admin 20 Oct 19 16:32 libclntsh.dylib -> libclntsh.dylib.10.1


Now you can compile the DBD::Oracle Package now:

$ cd ~/Download/DBD-Oracle-1.32
$ perl Makefile.PL
$ make
$ sudo make install


In perl script you connect to oracle server using the following code:

#! /usr/bin/perl -w

my $sid = "host=host.xyz.com;sid=DBSID;port=1521"
my $dbh = DBI->connect("dbi:Oracle:$sid", $user, $pass) or die "ERROR: failed to connect db: $@\n";


And you are likely see the following error:

dlopen(/Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle, 9): Library not loaded: libmysqlclient.16.dylib
Referenced from: /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle
Reason: image not found - /Library/Ruby/Gems/1.8/gems/mysql2-0.2.6/lib/mysql2/mysql2.bundle

You need to set the following in your .profile or .bash_profile

export DYLD_LIBRARY_PATH=/usr/local/mysql/lib:$DYLD_LIBRARY_PATH

see also http://lightyearsoftware.com/2011/02/mysql-5-5-on-mac-os-x/

http://dev.mysql.com/doc/refman/5.0/en/bit-functions.html

And the users' comments are very helpful!

SELECT
SUM(IF(rubrik & 1, 1, 0)) actus,
SUM(IF(rubrik & 2, 1, 0)) shopping,
SUM(IF(rubrik & 4, 1, 0)) utils,
SUM(IF(rubrik & 8, 1, 0)) communication,
SUM(IF(rubrik & 16, 1, 0)) services,
COUNT(user_id) AS total,
FROM preferences p

It is really cool!

For example I have a table Tbl_Cmp_Grp_Srt_Txt with four columns Cmp, Grp, Srt, Txt
Cmp has two different values "C1" and "C2", we want to group by Grp, sort by Srt and concat all the Txt's together and put the different groups side-by-side. Here is how I did it.

SELECT t1.Cmp, t1.Grp, t1.Txts, t2.Cmp, t2.Grp, t2.Txts
FROM
(SELECT Cmp, Grp, GROUP_CONCAT(Txt ORDER BY Srt separator '\t') Txts
FROM Tbl_Cmp_Grp_Srt_Txt
WHERE Cmp = 'C1' GROUP BY Grp) AS t1,
(SELECT Cmp, Grp, GROUP_CONCAT(Txt ORDER BY Srt separator '\t') Txts
FROM Tbl_Cmp_Grp_Srt_Txt
WHERE Cmp = 'C2' GROUP BY Grp) AS t1,
WHERE t1.Grp = t2.Grp
AND t1.Txts <> t2.Txts

DROP FUNCTION IF EXISTS getHostFromUrl;
CREATE FUNCTION getHostFromUrl (url text(1024)) RETURNS CHAR(255)
BEGIN
DECLARE str1 varchar(10);
DECLARE str2 varchar(10);
SET str1='http://';
SET str2='https://';
RETURN REPLACE(SUBSTRING_INDEX(REPLACE(url, str2, str1), '/', 3), str1, '');
END;

mysql> SELECT MD5('testing');

• You can find the official download Link at http://dev.mysql.com/downloads/
• For MySql 5.0: http://dev.mysql.com/downloads/mysql/5.0.html#downloads

Step 2: Install the Binary
shell> /usr/sbin/groupadd mysql
shell> /usr/sbin/useradd -g mysql mysql
shell> cd /usr/local
shell> gunzip < /PATH/TO/MYSQL-VERSION-OS.tar.gz | tar xvf -
shell> ln -s FULL-PATH-TO-MYSQL-VERSION-OS mysql
shell> cd mysql
shell> scripts/mysql_install_db --user=mysql
shell> chown -R root .
shell> chown -R mysql data
shell> chgrp -R mysql .
shell> bin/mysqld_safe --user=mysql & # start mysql daemon

Step 3: Post-installation
shell> su mysql
shell> mysql/scripts/mysql_install_db

shell> mysql -u root -p
mysql> use mysql
mysql> GRANT ALL PRIVILEGES ON *.* TO 'user'@'localhost' IDENTIFIED BY 'password' WITH GRANT OPTION;
mysql> set PASSWORD FOR 'user'@'localhost' = PASSWORD('password');
mysql> FLUSH PRIVILEGES;
mysql> select * from mysql.user;

mysql> create database db_name;
mysql> SHOW DATABASES;
mysql> use db_name;
mysql> SHOWTABLES;

What you want to do is to put number of rows for different values of Grade side by side.

You can use IF function to do so if you know all the possible values of Grade

SELECT
SUM(IF(Grade  = 1, 1, 0)) AS CntGrade1,
SUM(IF(Grade  = 2, 1, 0)) AS CntGrade2,
SUM(IF(Grade  = 3, 1, 0)) AS CntGrade3,
SUM(IF(Grade  NOT IN (1, 2, 3), 1, 0)) AS CntOthers
FROM Tbl_Facts

If you have a formula to calculate a score of your facts, say when Grade is 1, you get 10 points; when Grade is 2, you get 5, when Grade is 3 you get 0, otherwise you get -5. What is the total score of the rows in your table?

SELECT
SUM((CASE Grade   WHEN 1 THEN 10 WHEN 2 THEN 5 WHEN 3 THEN 0 ELSE -5 END)) AS Score,
FROM Tbl_Facts

SELECT @no:=@no+1 rownum, t.*
FROM (SELECT @no:=0) r, table_name t