gem 'mysql2 　がgemfileにないとなる

###エラー内容
Could not find gem 'mysql2 (>= 0.4.4, < 0.6.0)' in any of the gem sources listed in your Gemfile.
Run bundle install to install missing gems.

bundle installをすると

The dependency tzinfo-data (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java.
Fetching gem metadata from https://rubygems.org/............
Fetching gem metadata from https://rubygems.org/.
Resolving dependencies....
Using rake 13.0.1
Using concurrent-ruby 1.1.6
Using i18n 1.8.3
Using minitest 5.14.1
Using thread_safe 0.3.6
Using tzinfo 1.2.7
Using activesupport 5.2.4.3
Using builder 3.2.4
Using erubi 1.9.0
Using mini_portile2 2.4.0
Using nokogiri 1.10.9
Using rails-dom-testing 2.0.3
Using crass 1.0.6
Using loofah 2.6.0
Using rails-html-sanitizer 1.3.0
Using actionview 5.2.4.3
Using rack 2.2.3
Using rack-test 1.1.0
Using actionpack 5.2.4.3
Using nio4r 2.5.2
Using websocket-extensions 0.1.5
Using websocket-driver 0.7.2
Using actioncable 5.2.4.3
Using globalid 0.4.2
Using activejob 5.2.4.3
Using mini_mime 1.0.2
Using mail 2.7.1
Using actionmailer 5.2.4.3
Using activemodel 5.2.4.3
Using arel 9.0.0
Using activerecord 5.2.4.3
Using mimemagic 0.3.5
Using marcel 0.3.3
Using activestorage 5.2.4.3
Using bindex 0.8.1
Using msgpack 1.3.3
Using bootsnap 1.4.6
Using bundler 2.1.4
Using byebug 11.1.3
Using coffee-script-source 1.12.2
Using execjs 2.7.0
Using coffee-script 2.4.1
Using method_source 1.0.0
Using thor 1.0.1
Using railties 5.2.4.3
Using coffee-rails 4.2.2
Using ffi 1.13.1
Using jbuilder 2.10.0
Using rb-fsevent 0.10.4
Using rb-inotify 0.10.1
Using ruby_dep 1.5.0
Using listen 3.1.5
Fetching mysql2 0.5.3
Installing mysql2 0.5.3 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

current directory: /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/mysql2-0.5.3/ext/mysql2

/home/ec2-user/.rvm/rubies/ruby-2.6.3/bin/ruby -I
/home/ec2-user/.rvm/rubies/ruby-2.6.3/lib/ruby/site_ruby/2.6.0 -r
./siteconf20200623-6737-azqw8f.rb extconf.rb
--with-ldflags=-L/usr/local/opt/openssl/lib
checking for rb_absint_size()... yes
checking for rb_absint_singlebit_p()... yes
checking for rb_wait_for_single_fd()... yes

Using mysql_config at /usr/bin/mysql_config

checking for mysql.h... no
checking for mysql/mysql.h... no

mysql.h is missing. You may need to 'sudo apt-get install libmariadb-dev', 'sudo apt-get
install libmysqlclient-dev' or 'sudo yum install mysql-devel', and try again.

*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need 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=/home/ec2-user/.rvm/rubies/ruby-2.6.3/bin/$(RUBY_BASE_NAME)
--with-mysql-dir
--without-mysql-dir
--with-mysql-include
--without-mysql-include=${mysql-dir}/include
--with-mysql-lib
--without-mysql-lib=${mysql-dir}/lib
--with-mysql-config
--without-mysql-config

To see why this extension failed to compile, please check the mkmf.log which can be
found here:

/home/ec2-user/.rvm/gems/ruby-2.6.3/extensions/x86_64-linux/2.6.0/mysql2-0.5.3/mkmf.log

extconf failed, exit code 1

Gem files will remain installed in /home/ec2-user/.rvm/gems/ruby-2.6.3/gems/mysql2-0.5.3
for inspection.
Results logged to
/home/ec2-user/.rvm/gems/ruby-2.6.3/extensions/x86_64-linux/2.6.0/mysql2-0.5.3/gem_make.out

An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue.
Make sure that gem install mysql2 -v '0.5.3' --source 'https://rubygems.org/' succeeds
before bundling.

In Gemfile:
mysql2

自分がやっていたこと

rails _5.2.2_ new microposts --database=mysql --skip-test

rails db:create

sudo service mysqld start

rails s

エラーはどこで出たのか

rails sのところで出ました

原因かもしれないこと

前にrails sがうまくいかなかったのでネットで調べて書いてあるコードを全てやってみたことです

https://stackoverflow.com/questions/52051122/cant-find-gem-railties-0-a-with-executable-rails-gemgemnotfoundexceptio/52051721

これのコードを全て打ちました
初心者なのでわからないことがたくさんなので助けてください

maisumakun

2020/06/23 06:38

bundle installは行いましたか？

kai20000803

2020/06/23 08:13

しました bundle install をすると An error occurred while installing mysql2 (0.5.3), and Bundler cannot continue. Make sure that `gem install mysql2 -v '0.5.3' --source 'https://rubygems.org/'` succeeds before bundling. In Gemfile: mysql2 こうなりました