What is the oldest age of the users in 2014's survey?
what is your age? refer to QuestionText; 2014 refer to SurveyID; oldest age refers to MAX(AnswerText)


SELECT T2.AnswerText FROM Question AS T1 INNER JOIN Answer AS T2 ON T1.questionid = T2.QuestionID WHERE T1.questiontext = 'What is your age?' AND T2.SurveyID = 2014 ORDER BY T2.AnswerText DESC LIMIT 1