Multiple MySQL Versions with Homebrew

homebrew_multiple_mysql_versions.md

Multiple MySQL Versions with Homebrew

For homebrew version 1.5.12 - WIP... not quite working yet.

brew -v # => Homebrew 1.5.12

Install the current version of mysql.

# Install current mysql version
brew install mysql

# Start agent for current version of mysql (including on login)
brew services start mysql

Install the older version of mysql.

# Find older mysql versions
brew search mysql  
  
# Install older mysql version
brew install mysql@5.6 5.6.39

# Start agent for older version of mysql (including on login)
brew services start mysql@5.6

Then to switch to the older version.

# Unlink current mysql version
brew unlink mysql 

# Check older mysql version
ls /usr/local/Cellar/mysql@5.6 # => 5.6.39

# Link the older version
brew switch mysql 5.7.21

And to switch back to the current version.

# Unlink older mysql version
brew unlink mysql@5.6 

# Check current mysql version
ls /usr/local/Cellar/mysql # =>  5.7.21

# Link the current version
brew switch mysql 5.7.10

To verify which mysql version you're on at any time.

# Check which version of mysql is currently symlinked
ls -l /usr/local/bin/mysql # => /usr/local/bin/mysql@ -> ../Cellar/mysql56/5.6.27/bin/mysql

# Or using the mysql command
mysql --version

And to unload a mysql agent for a given version.

# Stop agent for current version of mysql
launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.mysql.plist
rm ~/Library/LaunchAgents/homebrew.mxcl.mysql.plist

# Stop agent for older version of mysql
launchctl unload ~/Library/LaunchAgents/homebrew.mxcl.mysql56.plist
rm ~/Library/LaunchAgents/homebrew.mxcl.mysql56.plist

MySQL 5.7:

To have launchd start mysql now and restart at login:
brew services start mysql

Or, if you don't want/need a background service you can just run:
mysql.server start

MySQL 5.6:

To have launchd start mysql@5.6 now and restart at login:
brew services start mysql@5.6

Or, if you don't want/need a background service you can just run:
/usr/local/opt/mysql@5.6/bin/mysql.server start

A few of these sections don't look right. For example in "Then to switch to the older version", you "find" version 5.6.39 but then you switch to 5.7.21. Shouldn't that last statement be brew switch mysql@5.6 5.6.39?

my way around this was as simple as:
brew services stop mysql
brew install mysql@5.7 (since the upgraded mysql 8 was already installed as "mysql")
brew unlink mysql
brew link -force mysql@5.7
brew services start mysql@5.7

the problem initially was "brew switch mysql 5.7.23" did not work for me with error that "cellar does not contain that version"...