Question: What % of respondents want to keep using their current programming language by programming language? 
SQL:
SELECT Languages.name, COUNT(Languages.id) * 100.0 / count2 FROM Languages JOIN Response_LanguageHaveWorkedWith ON Response_LanguageHaveWorkedWith.Languages_id = Languages.id JOIN Response_LanguageWantToWorkWith ON Response_LanguageWantToWorkWith.Response_id = Response_LanguageHaveWorkedWith.Response_id AND Response_LanguageWantToWorkWith.Languages_id = Languages.id JOIN (SELECT Languages.name AS name2, COUNT(Languages.id) AS count2 FROM Languages JOIN Response_LanguageHaveWorkedWith ON Response_LanguageHaveWorkedWith.Languages_id = Languages.id GROUP BY Languages.id) ON Languages.name = name2 GROUP BY Languages.id