一、下载安装mysql

二、安装mysql2

      在windows 安装

     gem install mysql2  -- \ --with-mysql-dir=D:\mysql 

 

     在linux下安装

     gem install mysql2 -- \ --with-mysql-lib=/var/lib/mysql -- \ --with-mysql-include=/usr/include/mysql

 

    错误报告：

This could take a while...

ERROR:  Error installing mysql2:        ERROR: Failed to build gem native extension.

    /usr/local/ruby/bin/ruby extconf.rb  --with-mysql-dir=/var/lib/mysql --  --with-mysql-include=/usr/include/mysql

checking for ruby/thread.h... yeschecking for rb_thread_call_without_gvl() in ruby/thread.h... yeschecking for rb_thread_blocking_region()... yeschecking for rb_wait_for_single_fd()... yeschecking for rb_hash_dup()... yeschecking for rb_intern3()... yes-----Cannot find include dir at /usr/include/mysql:/usr/include/mysql:/var/lib/mysql/include-----*** extconf.rb failed ***Could not create Makefile due to some reason, probably lack of necessarylibraries and/or headers.  Check the mkmf.log file for more details.  You mayneed configuration options.

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/local/ruby/bin/ruby        --with-mysql-dir        --with-mysql-include=${mysql-dir}/include        --with-mysql-lib        --without-mysql-lib=${mysql-dir}/lib

extconf failed, exit code 1

Gem files will remain installed in /usr/local/ruby/lib/ruby/gems/2.1.0/gems/mysql2-0.3.15 for inspection.

Results logged to /usr/local/ruby/lib/ruby/gems/2.1.0/extensions/x86-linux/2.1.0-static/mysql2-0.3.15/gem_make.out

 

     因为确实mysql头文件, 先确认是否安装了mysql-devel，安装后，看是否指定了头文件的目录。

 

      注意：务必安装 mysql-devel包