Mysql sql查詢時 if 的用法

SELECT qanswers.id,qanswers.question_id,qanswers.answer,users.nickname AS replier,  
  
users.groupname,IF(users.groupname='teacher',TRUE,FALSE) AS isTeacher  
  
FROM fa_user_question_answer AS qanswers   
  
LEFT JOIN fa_users AS users ON users.id=qanswers.user_id   
  
WHERE qanswers.question_id=11