I try to run gem 'thinking-sphinx' on my Ruby on Rails project, but something was wrong. When I run any search command on any model, I see this error: ThinkingSphinx::SphinxError (Unknown MySQL error).
More details:
MacOS Mojave -v 10.14.3
mysql -v 8.0.15 (Installed first)
Sphinx -v 2.2.11_2 (Installed via 'brew install sphinx')
thinking-sphinx -v 4.2.0
Rails -v 5.2.2
Before run search command, I runned rails ts:index and rails ts:start
What am I doing wrong?
Sphinx v2.2 (and 3.0) is not compatible with MySQL v8. You'll either want to downgrade MySQL to 5.7 - which can be done with homebrew via brew install mysql#5.7 - and then uninstall and reinstall Sphinx, or download the binaries for Sphinx v3.1.1 (the first version to support MySQL v8) from the Sphinx website (the source code for that release is not currently available, hence it's not installable via homebrew).
Just changed mysql2 from gem "mysql2", '~> 0.4.6' to gem "mysql2", '0.4.10' version, and it worked for me. Thanks
I am having some problems when trying to install mysql2 gem for Rails. When I try to install it by running bundle install or gem install mysql2 it gives me the following error:
Error installing mysql2: ERROR: Failed to build gem native extension.
How can I fix this and successfully install mysql2?
On Ubuntu/Debian and other distributions using aptitude:
sudo apt-get install libmysql-ruby libmysqlclient-dev
Package libmysql-ruby has been phased out and replaced by ruby-mysql. This is where I found the solution.
If the above command doesn't work because libmysql-ruby cannot be found, the following should be sufficient:
sudo apt-get install libmysqlclient-dev
On Red Hat/CentOS and other distributions using yum:
sudo yum install mysql-devel
On Mac OS X with Homebrew:
brew install mysql
I'm on a mac and use homebrew to install open source programs. I did have to install mac Dev tools in order to install homebrew, but after that it was a simple:
brew install mysql
to install mysql. I haven't had a mysql gem problem since.
here is a solution for the windows users, hope it helps!
Using MySQL with Rails 3 on Windows
Install railsinstaller -> www.railsinstaller.org (I installed it to c:\Rails)
Install MySQL (I used MySQL 5.5) -> dev.mysql.com/downloads/installer/
--- for mySQL installation ---
If you dont already have these two files installed you might need them to get your MySQL going
vcredist_x86.exe -> http://www.microsoft.com/download/en/details.aspx?id=5555
dotNetFx40_Full_x86_x64.exe -> http://www.microsoft.com/download/en/details.aspx?id=17718
Use default install
Developer Machine
-MySQL Server Config-
port: 3306
windows service name: MySQL55
mysql root pass: root (you can change this later)
(username: root)
-MySQL Server Config-
--- for mySQL installation ---
--- Install the mysql2 Gem ---
Important: Do this with Git Bash Command Line(this was installed with railsinstaller) -> start/Git Bash
gem install mysql2 -- '--with-mysql-lib="c:\Program Files\MySQL\MySQL Server 5.5\lib" --with-mysql-include="c:\Program Files\MySQL\MySQL Server 5.5\include"'
Now the gem should have installed correctly
Lastly copy the libmysql.dll file from
C:\Program Files\MySQL\MySQL Server 5.5\lib
to
C:\Rails\Ruby1.9.2\bin
--- Install the mysql2 Gem ---
You will now be able to use your Rails app with MySQL, if you are not sure how to create a Rails 3 app with MySQL read on...
--- Get a Rails 3 app going with MySQL ---
Open command prompt(not Git Bash) -> start/cmd
Navigate to your folder (c:\Sites)
Create new rails app
rails new world
Delete the file c:\Sites\world\public\index.html
Edit the file c:\Sites\world\config\routes.rb
add this line -> root :to => 'cities#index'
Open command prompt (generate views and controllers)
rails generate scaffold city ID:integer Name:string CountryCode:string District:string Population:integer
Edit the file c:\Sites\world\app\models\city.rb to look like this
class City < ActiveRecord::Base
set_table_name "city"
end
Edit the file c:\Sites\world\config\database.yml to look like this
development:
adapter: mysql2
encoding: utf8
database: world
pool: 5
username: root
password: root
socket: /tmp/mysql.sock
add to gemfile
gem 'mysql2'
Open command prompt windows cmd, not Git Bash(run your app!)
Navigate to your app folder (c:\Sites\world)
rails s
Open your browser here -> http://localhost:3000
--- Get a Rails 3 app going with MySQL ---
For MacOS Mojave:
gem install mysql2 -v '0.5.2' -- --with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include
On Ubuntu(18.04)
i was able to solve this issue by running the following:
sudo apt-get install build-essential libmysqlclient-dev
gem install mysql2
reference
Another way for MacOS users
If you used "brew" to install mysql:
gem install mysql2 -v 'x.x.x' -- --with-mysql-config=/usr/local/Cellar/mysql/y.y.y/bin/mysql_config
x.x.x = version of the mysql2 gem you want to install
y.y.y = the version of mysql you have installed ls /usr/local/Cellar/mysql to find it.
I have several computers, 32 and 64 bits processor, they run on Ubuntu Linux, Maverick (10.10) release.
I had the same problem, and for me, the
sudo apt-get install libmysql-ruby libmysqlclient-dev
did the job!!!
Have you tried using
gem install mysql -- --with-mysql-lib=/usr/lib/mysql/lib
to specify the location of thebase directory as well as the path to the MySQL libraries that are necessary to complete the gem installation?
Sources:
MySQL Gem Install ERROR: Failed to build gem native extension
MySQL Forums :: Ruby :: Help needed with installing MySQL binding for Ruby
If you are using yum try:
sudo yum install mysql-devel
This solved my problem once in Windows:
subst X: "C:\Program files\MySQL\MySQL Server 5.5"
gem install mysql2 -v 0.x.x --platform=ruby -- --with-mysql-dir=X: --with-mysql-lib=X:\lib\opt
subst X: /D
On Debian Stretch the package that worked for me was default-libmysqlclient-dev
sudo apt-get update && apt-get install -y default-libmysqlclient-dev
If you are still having trouble….
Try installing
sudo apt-get install ruby1.9.1-dev
In my case this helped:
$ export LDFLAGS="-L/usr/local/opt/openssl/lib"
$ export CPPFLAGS="-I/usr/local/opt/openssl/include"
Then:
gem install mysql2 -v '0.5.2' --source 'https://rubygems.org/' -- --with-cppflags=-I/usr/local/opt/openssl/include --with-ldflags=-L/usr/local/opt/openssl/lib
Result:
Building native extensions with: '--with-cppflags=-I/usr/local/opt/openssl/include --with-ldflags=-L/usr/local/opt/openssl/lib'
This could take a while...
Successfully installed mysql2-0.5.2
Parsing documentation for mysql2-0.5.2
Installing ri documentation for mysql2-0.5.2
Done installing documentation for mysql2 after 0 seconds
1 gem installed
See this post (WARNING: Japanese language inside).
I had this issue on Windows 7. This is apparently an incompatibility issue and the solution is as follows:
Download the libmySQL.dll file from an older InstantRails installer. It is available from the InstantRails GitHub repo.
Next, copy that file into your Ruby/bin folder.
Now, you are good to go ;)
I got this error too. Solved by installing development packages. I'm using arch and it was:
sudo pacman -S base-devel
which installed:
m4, autoconf, automake, bison, fakeroot, flex, libmpc, ppl, cloog-ppl, elfutils, gcc,
libtool, make, patch, pkg-config
but I think it actually needed make and gcc. Error output said (on my machine, among other):
"You have to install development tools first."
So it was an obvious decision and it helped.
You have to Install some dependencies
sudo apt-get install libmysql-ruby libmysqlclient-dev
I can see most of the people have found the solution to this problem, this is mostly coused but not limited to missing packages, this happened to me after I have purged mysql and reinstalled it. I had to run this command in order to fix my problem:
sudo apt-get install libmysqlclient-dev
This command helped me fix my problem
I was running into this error on my mac and found that I needed to upgrade from mysql 32bit to mysql 64 bit to get this error to go away. I was running OSX 10.6 on an intel macbook pro with ruby 1.9.2 and rails3.0.0
I also needed to install xcode in order to get unix utilities like "make" that are required to compile the gem.
once this was done I was able to run gem install mysql and gem install mysql2 without error.
I got the gem built on Mac OS X 10.6.6 by
1) Ensuring the Developer tools package is installed
2) Downloading the current MySQL package (5.5.8 in my case) from Source
3) Installing the cmake tool from cmake.org
4) Following the instructions in section 2.11 of INSTALL-SOURCE from the mysql distribution files
5) sudo gem install mysql2 -- --srcdir=/usr/local/mysql/include
The gem built successfully, but there are two errors in the documentation that rdoc and ri complain about.
But now when I try to require 'mysql2' I get a
LoadError: no such file to load -- mysql2/mysql2
I was hoping the error I would get was that the libmysqlclient.16.dylib couldn't be found because we figured that out in another post (search for install_name_tool).
My $PATH has /usr/local/mysql in it (that's where my source and built files are located), so I'm a little stumped. If anyone has any thoughts, I'll check back after a few hours of sleep.
For windows user:
You set the lib and include path of your mysql, for instance, if youre using xampp you can have like this:
gem install mysql2 -- '--with-mysql-lib="C:\xampp\mysql\lib" --withmysql-include="C:\xampp\mysql\include"'
Solution only works on Mac OS X
If you've installed MySQL with homebrew, what worked for me was uninstalling MySQL, and installing MySQL Community Edition via the MySQL website (https://www.mysql.com/).
After installed, just re-enter the command to gem install mysql2 or if necessary, sudo gem install mysql2, if you are getting permission denied problems.
If still getting error then follow the steps of mysql2 gem installation on Rails 3 on -
http://rorguide.blogspot.com/2011/03/installing-mysql2-gem-on-ruby-192-and.html
where most of the user were able to install mysql2 gem.
After you get the mysql-dev issues corrected, you may need to remove the bad mysql2 install. Look carefully at the messages after $ bundle install. You may need to
rm -rf vendor/cache/
rm -rf ./Zentest
This will clear out the bad mysql2 installation so that a final $ bundle install can create a good one.
download the right version of mysqllib.dll then copy it to ruby bin really works for me. Follow this link plases mysql2 gem compiled for wrong mysql client library
Got the "You have to install development tools first." error when trying to install the mysql2 gem after upgrading to Mac OS X Mountain Lion. Apparently doing this upgrade removes the command line compilers.
To fix:
I uninstalled my very old version of Xcode (ran the uninstall script in /Developer/Library). Then deleted the /Developer directory.
Went to the AppStore and downloaded Xcode.
Launched Xcode and went into the Preferences -> Downloads, and installed the command line tools.
You are getting this problem because you have not install MySql. Before install mysql2 gem. Install MySQL. After that mysql2 gem will install.
I just wanted to add this answer specifically for Mac Users.
My server was running perfectly fine until I updated my xcode. The while starting my rails server the error was shown like this
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
/Users/user/.rvm/rubies/ruby-1.9.3-p448/bin/ruby extconf.rb --with-mysql-
checking for rb_thread_blocking_region()... /Users/user/.rvm/rubies/ruby-1.9.3-
p448/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an
executable file. (RuntimeError)
And there was suggestion to install mysql2 gem at the end of the error message. So when i tried installing it I got the error as above mentioned in this question. The error I got is as follows
ERROR: Error installing mysql2:
ERROR: Failed to build gem native extension.
So as suggested in this post I tried 'brew install mysql' and that quitted saying that mysql version so and so already installed. But there was warning before it saying
Warning: You have not agreed to the Xcode license.
Builds will fail! Agree to the license by opening Xcode.app or running:
xcodebuild -license
Then I tried this sudo xcodebuild -license and type 'agree' at the end. You have to be root to agree to the license.
After this, I again tried bundle install and then everything is working fine as normal. [ Even due to this xcode updation, I had problem with my tower also.]
libmysql-ruby has been phased out and replaced. New command:
sudo apt-get install ruby-mysql libmysqlclient-dev
Under ubuntu 20.04 LTS it's the only solution that have been working for me:
sudo apt-get install ruby-mysql2
According to https://github.com/brianmario/mysql2/issues/1175 , I fixed it by
gem install mysql2 -- \
--with-mysql-lib=/usr/local/Cellar/mysql/8.0.26/lib \
--with-mysql-dir=/usr/local/Cellar/mysql/8.0.26 \
--with-mysql-config=/usr/local/Cellar/mysql/8.0.26/bin/mysql_config \
--with-mysql-include=/usr/local/Cellar/mysql/8.0.26/include
I upgraded to Snow Leopard using the disc we got at WWDC.
Trying to run some of my rails apps now complains about sql
(in /Users/coneybeare/Projects/Ambiance/ambiance-server)
!!! The bundled mysql.rb driver has been removed from Rails 2.2. Please install the mysql gem and try again: gem install mysql.
Importing all sounds in /Users/coneybeare/Projects/Ambiance/ambiance-sounds/Import 32/Compressed/
-- AdirondackPeepers.caf
!!! The bundled mysql.rb driver has been removed from Rails 2.2. Please install the mysql gem and try again: gem install mysql.
rake aborted!
dlopen(/opt/local/lib/ruby/gems/1.8/gems/mysql-2.7/lib/mysql.bundle, 9): Library not loaded: /usr/local/mysql/lib/libmysqlclient.16.dylib
Referenced from: /opt/local/lib/ruby/gems/1.8/gems/mysql-2.7/lib/mysql.bundle
Reason: image not found - /opt/local/lib/ruby/gems/1.8/gems/mysql-2.7/lib/mysql.bundle
(See full trace by running task with --trace)
I could have sworn I fixed this once before. The problem is that
sudo gem install mysql
does not work and gives the error:
Building native extensions. This could take a while...
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.
/opt/local/bin/ruby extconf.rb install mysql
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lm... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lz... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lsocket... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lnsl... no
checking for mysql_query() in -lmysqlclient... no
Gem files will remain installed in /opt/local/lib/ruby/gems/1.8/gems/mysql-2.7 for inspection.
Results logged to /opt/local/lib/ruby/gems/1.8/gems/mysql-2.7/gem_make.out
Has anybody gotten mysql to work with rails on snow leopard yet? If so, what is your setup and better yet, what can I do to reproduce it?
I just went through the same pain... here's what worked for me:
Download / install the 64-bit MySQL 5.1.37 from mysql.com
run the following commands:
sudo gem update --system
sudo env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-config=/usr/local/mysql/bin/mysql_config
I also uninstalled all mysql gems that were floating around from my 10.5 days, that may do it if the above doesn't work for you :)
Rebuilding mysql as 64bit or installing the 64bit version is important, but you also need to make sure you build the native parts of the mysql gem as 64bit as well (this doesn't apply if you are on one of the original Intel Core Duo macs).
Here's the magic command:
env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-config=/usr/local/mysql/bin/mysql_config
You should set the ARCHFLAGS as shown above whenever you do a gem install with native components on Snow Leopard.
If you're using bundler, you can use "bundle config" to set the proper build arguments for mysql like so:
bundle config build.mysql --with-mysql-config=/usr/local/mysql/bin/mysql_config
I fought with this for a long time and finally got it working on Snow Leopard. I ended up installing Ruby, RubyGems, and MySQL from source (see the Hivelogic tutorial for installing Ruby and RubyGems. The MySQL tutorial is linked at the bottom). I finally got the gem to install, but I was still getting
dyld: lazy symbol binding failed: Symbol not found: _mysql_init
Referenced from: /Library/Ruby/Site/1.8/universal-darwin10.0/mysql.bundle
Expected in: flat namespace
dyld: Symbol not found: _mysql_init
Referenced from: /Library/Ruby/Site/1.8/universal-darwin10.0/mysql.bundle
Expected in: flat namespace
Trace/BPT trap
I finally deleted the mysql.bundle (I have no idea what this is for) and it all worked.
sudo rm -f /Library/Ruby/Site/1.8/universal-darwin10.0/mysql.bundle
Hope that helps someone.
I have seen this problem many times. almost everytime I build mysql on a machine. I think, you have to pass your mysqlconfig as part of the gem install command.
sudo gem install mysql -- --with-mysql-config=/your/mysql/config
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/usr/bin/ruby
--with-mysql-config
Remember that you need mysql dev files to be able to build this gem.
I was having problems with getting my configuration to work after installing snow leopard. I found MAMP at http://www.mamp.info and it bundles Apache, PHP and MySQL. you install it like an application and it just works. Maybe worth giving it a try, and it is free.
mesh
I thought I would answer my own question here. It seems as if the problem isnt in mysql, but in the mysql ruby bindings. I figured this out because when I hooked up Querius (my mysql gui), it was able to connect.
Here is how to build from source fix the bindings:
cd /tmp
wget http://www.tmtm.org/en/ruby/mysql/ruby-mysql-0.2.6.tar.gz
tar xvfz ruby-mysql-0.2.6.tar.gz
cd ruby-mysql-0.2.6
./configure
make
sudo make install
There are plenty of libraries that I will have to build from source on Snow Leopard and they keep popping up. MacPorts doesnt seem to be updated enough for all the libs so I'm off to do it on my own. Next up: freetype (http://download.savannah.gnu.org/releases-noredirect/freetype/)
I proceeded like explained in this post (http://www.schmidp.com/2009/06/14/rubyrails-and-mysql-on-snow-leopard-10a380/), and everything now works fine.
Remember to lookout for the typos in his command to install the mysql driver.
I had this same issue and here is what worked for me.
Install Snow Leopard and the 64bit MySQL DMG.
Create /etc/my.cnf to point to my previous MySQL data directory (as described here) and run sudo mysql_upgrade.
Opened IRB and reinstall all of my gems using (via blog.costan.us/2009/07/rebuild-your-ruby-gems-if-you-update-to.html).`gem list`.each_line {|line| system 'sudo gem install #{line.split.first}'}
Uninstalled the MySQL gems I had installed.
Installed MySQL gem with sudo env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-config=/usr/local/mysql/bin/mysql_config
With that, everything seems to be working so far. *knock wood*
In case you prefer homebrew, instead of installing MySQL manually.
Un-install the existing mysql gem (if any):
sudo gem uninstall mysql
Locate the ‘mysql_config’ file:
find /usr -name 'mysql_config'
Re-install mysql gem:
sudo env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-config=/usr/local/bin/mysql_config
Note: replace /usr/local/bin/ with the corresponding mysql_config path found in step 2. Also on my blog.
Ian Selby thank you alot but I had to remove the sudo from in front of sudo env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-config=/usr/local/mysql/bin/mysql_config
I was installing to a gemset and am using rvm which I think asks you not to use the sudo keyword. Thanks alot.
I've solved it this way:
after install dmg file of mysql
bundle config build.mysql --with-mysql-config=/usr/local/mysql/bin//mysql_config
env ARCHFLAGS="-arch x86_64"
bundle install
Having had a break from Rails for several years, I just spent some time setting up my development environment. So thought I would create a tutorial on how to install the latest version of Rails 3, MySQL, and RVM on SnowLeopard, to hopefully save others some time who are in my position.
It works as of 21st August 2011, using Rails 3.0.10, MySQL 5.5.15, and RVM 1.7.2. It should work with future Rails 3.0.x, MySQL 5.5.x, and RVM 1.7.x versions.
Install XCode if not already installed. I used 4.0.2. Unfortunately this has now been withdrawn by Apple, but may be available elsewhere on the Internet. Version 3.2.x is free to download from Apple, but I did not test it with this tutorial, it probably works too.
Install rvm:
user$ bash < <(curl -s https://rvm.beginrescueend.com/install/rvm)
user$ echo '[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm" # Load RVM function' >> ~/.bash_profile
user$ source .bash_profile
Install a version of Ruby (e.g. 1.9.2) in rvm, basic usage instructions are here.
user$ rvm install 1.9.2
user$ rvm use 1.9.2
Create a gemset for the rvm ruby installed in step 2 (x is the version number).
user$ rvm gemset create rails30x
user$ rvm 1.9.2#rails30x
Install Rails 3.0.x (x is the version number).
user$ gem install rails -v 3.0.x.
Download and install the MySQL 5.5.x package, the startup item, and the preferences pane. All 3 of these are included in the DMG install file. Also install MySQL WorkBench.
Find /usr/local/mysql-version-name/support-files (inserting the correct MySQL directory name) and edit mysql.server (with root privileges). Around line 46 locate the lines that read:
basedir=
datadir=
and change them to read (inserting the correct MySQL directory name):
basedir=/usr/local/mysql-version-name
datadir=/usr/local/mysql-version-name/data
Save the file. MySQL can now be started from the preferences pane.
To enable rails 3 to use mysql, install the mysql2 gem (see next step). First, you’ll need to set the
DYLD_LIBRARY_PATH to include the MySQL library directory. To do this, edit your ~/.bash_profile in your
home folder and include the following (inserting the correct MySQL directory name):
export DYLD_LIBRARY_PATH=/usr/local/mysql-version-name/lib:$DYLD_LIBRARY_PATH
Without the inclusion of the directory in the DYLD_LIBRARY_PATH, a message about not finding the library
would appear and the server would abort.
Install the mysql2 gem. (as of May 2011, version 0.2.7 is the most recent working version with Rails 3.0.x).
user$ gem install mysql2 -v 0.2.7
Create a rails app, and it's corresponding database (appname_development).
user$ rails new appname
Add this to the app's Gemfile: gem 'mysql2', "0.2.7"
Add this to the app's database.yml:
development:
adapter: mysql2
encoding: utf8
reconnect: false
database: appname_development
pool: 5
username: username
password: pwd
host: localhost
start app and check "About your application's environment". Everything should be working correctly.
The instructions for setting ARCHFLAGS and passing --mysql-config=... didn't seem to be quite enough to solve this for me on Snow Leopard. In addition to doing that, I added:
DYLD_LIBRARY_PATH="/usr/local/mysql/lib:$DYLD_LIBRARY_PATH"
to my bash profile, and this solved it for me.
I tried the archflags trick many times with slight variations but it never worked for me.
What finally did work was switching back to the version of ruby and gem installed with snow leopard.
I had built and installed my own version which has worked for me in every respect except this one.
Since everything else seems to work fine, I can't help guessing the mysql plugin has some funky assumptions in it. Anyway, all I did was switch /usr/bin to be first in my path again. I had installed ruby in /usr/local/ruby-1.8.7 and /usr/local/ruby-1.9.1 to be able to easily switch. Thought I'd mention it since the archflags solution seems to work for many people, but not quite all.
I renamed the mysql_config program from $MYSQL_HOME/bin to something else so that the configuration script from the gem installer is unable to find it. Even though I was using the libs option, the gem installer did always use the compile settings from my mysql installation, which is fat binary. But the default ruby installation is only x86_64 and therefore the compile of the gem fails. After renaming the mysql_config program the following command worked just fine and installed the gem:
sudo env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-dir=/usr/local/mysql
If you are installing the mysql gem with RVM you need to use the following code to install it
sudo env ARCHFLAGS="-arch x86_64" gem install mysql
This method worked for me in Leopard Server, none of the above worked
this article solved the issue for me :)
http://techliberty.blogspot.com/2009/12/dealing-with-rake-aborted-uninitialized.html
Prior to Leopard
sudo gem install mysql -- --with-mysql-dir=/usr/local/mysql
Leopard on a PPC machine:
sudo env ARCHFLAGS="-arch ppc" gem install mysql -- --with-mysql-config=/usr/local/mysql/bin/mysql_config
Leopard on an Intel machine:
sudo env ARCHFLAGS="-arch i386" gem install mysql -- --with-mysql-config=/usr/local/mysql/bin/mysql_config
Snow Leopard (only on Intel):
sudo env ARCHFLAGS="-arch x86_64" gem install mysql -- --with-mysql-config=/usr/local/mysql/bin/mysql_config