Question: How many respondents want to work with the various programming languages and which language are they currently using?
SQL:
SELECT Languages1.name AS have_worked_with, Languages2.name AS want_to_work_with, COUNT(*) FROM Response_LanguageHaveWorkedWith JOIN Languages AS Languages1 ON Response_LanguageHaveWorkedWith.Languages_id = Languages1.id JOIN Response_LanguageWantToWorkWith ON Response_LanguageWantToWorkWith.Response_id = Response_LanguageHaveWorkedWith.Response_id JOIN Languages AS Languages2 ON Response_LanguageWantToWorkWith.Languages_id = Languages2.id GROUP BY Languages1.name, Languages2.name