mysql - 为什么它在两行中显示相同的结果？

Question

嗨，我有这样的 sql 代码：

SELECT vote_id, (SELECT type FROM vote_types WHERE id= 1) AS answer
FROM poll_answers
WHERE question_id =1;

它向我显示：

如何提出这个问题，以便它可以在第二行显示另一个 answer2 which vote_id = 2 而不再显示 answer1 ？

谢谢

Answer 1

我不知道你的桌子。但我认为 - 查询应该是

SELECT vote_id, type as answer 
    FROM poll_answers, vote_types
    WHERE question_id =1 and question_id = id;

Answer 2

SELECT poll_questions.id, vote_types.type AS answer
FROM   poll_questions
  JOIN poll_answers ON poll_questions.id    = poll_answers.question_id
  JOIN vote_types   ON poll_answers.vote_id = vote_types.id
WHERE  poll_questions.referendum_id = 1