installing rails on OSX with mysql

trying to install and use ruby on rails on OSX with a mysql installation made by hand in /usr/local/mysql

$ rails server/Library/Ruby/Gems/1.8/gems/mysql2-0.3.11/lib/mysql2/mysql2.bundle: dlopen(/Library/Ruby/Gems/1.8/gems/mysql2-0.3.11/lib/mysql2/mysql2.bundle, 9): Library not loaded: /usr/local/mysql-5.5.17-osx10.6-x86/lib/libmysqlclient.18.dylib (LoadError)  

Referenced from: /Library/Ruby/Gems/1.8/gems/mysql2-0.3.11/lib/mysql2/mysql2.bundle  

Reason: no suitable image found.

I'm probably missing something about a correct installation on osx and with a correct distribution of mysql libraries but I've seen that the fastest way of getting rid of this problem was a:

sudo ln -s /usr/local/mysql/lib/libmysqlclient.18.dylib /usr/lib/libmysqlclient.18.dylib

use the

sudo install_name_tool -change libmysqlclient.18.dylib /usr/local/mysql-5.5.15-osx10.6-x86_64/lib/libmysqlclient.18.dylib /Library/Ruby/Gems/1.8/gems/mysql2-0.3.11/lib/mysql2/mysql2.bundle

should be the proper solution

DBD::mysql on Leopard

I've encountered this problem

dyld: lazy symbol binding failed: Symbol not found: _mysql_init Referenced from: /Library/Perl/5.8.8/darwin-thread-multi-2level/auto/DBD/mysql/mysql.bundle Expected in: dynamic lookup

dyld: Symbol not found: _mysql_init Referenced from: /Library/Perl/5.8.8/darwin-thread-multi-2level/auto/DBD/mysql/mysql.bundle Expected in: dynamic lookup

I always have problems due to multiple installation of mysql my hand, 32 and 64 bit, and 2 different installations of perl (one coming from Leopard, the other from port).

To solve this (due to 64bit mysql libraries and missing 32bit libs) I decided to recompile DBD::mysql on my box in CPAN

CPAN> force install DBD::mysql

and apparently this solved the problem

will Mysql die ?

http://monty-says.blogspot.com/2009/12/help-saving-mysql.html

reset mysql password

just a short memo, as usual:

stop mysql

restart in safe mode:

mysqld_safe --skip-grant-tables &

enter as root, now:

mysql -u root

and reset table password:

use mysql
update user set password=PASSWORD('newpassword') where user='root';

install LAMP (Apache - mysql - php) on Ubuntu

sudo apt-get install apache2

sudo apt-get install php5

sudo apt-get install mysql-server-5.0

sudo apt-get install libapache2-mod-php5

sudo /etc/init.d/apache2 restart

last n records in a query

I'm using mysql for this:

This is straightforward:

SELECT * FROM tab LIMIT 0, 10

will display the first 10 rows from the table tab.

SELECT * FROM tab LIMIT 5, 2

display rows 6 and 7 (5 is the offset, 2 the count)

And:

select * from (select * from TAB order by id desc limit 5 ) TA order by id;

display the LAST 5 rows.

MYSQL: convert null as 0

IFNULL():

like in:
SELECT IFNULL(field, 0) FROM tab;