windows：C:\Users\User\AppData\Roaming\MySQL\Workbench\wb_options.xml
mac：~/Library/Application\ Support/MySQL/Workbench/wb_options.xml
其他平台，可以find 一下wb_options.xml這個文件。
<value type="string" key="workbench.general.Editor:Font">Verdana</value>
找到key：workbench.general.Editor:Font，修改他的只即可。
PS:另外可以直接在設置里面設定：
actually you can change the font in MySQL Workbench, it is just not that obvious. Click twice (slowly, no double click) on the font name and it will become editable (this is similar to renaming something in Explorer). Added a nice font picker popup is on the todo list.