mysql查询以计算正确答案的分数

Question

我有一张桌子有问题，另一张桌子有正确答案 如果有任何用户尝试提问，那么我需要带分数的结果。

create table questions (question_id int, question_title varchar(50), marks int);

insert into questions values
(1, 'Question 1', 5),
(2, 'Question 2', 5);
create table answers (answer_id int, question_id int, is_true int, answer_title varchar(50));
insert into answers values
(1,1,0,'a'),
(2,1,1,'b'),
(3,2,1,'p'),
(4,2,1,'q');

create table user_quiz_attempt (attempt_id int, question_id int, answer_id int, user_id int);
insert into user_quiz_attempt values
(1,1,2,12),
(2,2,3,12),
(3,1,2,13),
(4,2,3,13),
(5,2,4,13);

我想要结果：-

显示错误结果：-

我的查询：-

select 
  sum(questions.marks) 
from 
  questions 
  inner join answers 
    on questions.question_id = answers.question_id 
  inner join user_quiz_attempt 
    on answers.answer_id = user_quiz_attempt.answer_id 
where 
  answers.is_true = 1 
  and user_quiz_attempt.user_id = 12/13

Answer 1

这是我的尝试：

http://sqlfiddle.com/#!9/e07258/2

SELECT 
  user_quiz_attempt.user_id,
  SUM(questions.marks) 
FROM user_quiz_attempt
INNER JOIN answers 
ON answers.answer_id = user_quiz_attempt.answer_id 
    AND answers.is_true = 1 
INNER JOIN questions  
ON questions.question_id = answers.question_id 
WHERE user_quiz_attempt.user_id IN (12,13)
GROUP BY user_quiz_attempt.user_id;

预期结果与当前结果的问题只是您的数据：

(1,1,0,'a'),
(2,1,1,'b'),
(3,2,1,'p'), <--
(4,2,1,'q'); <--

因此，Qustion 2的两个答案都是is_true。如果将(3,2,1,'p')更改为(3,2,0,'p')，将获得预期的结果。

http://sqlfiddle.com/#!9/1ab10b/1