Question

我们怎样才能找到有多少用户在轮询中选择了相同的答案，以及在mysql查询中有多少问题是相同的。这是我正在运行查询的表格。


  id          questionid              answerid             userid
  1              1762                   3514                156        
  2              1761                   3512                156
  3              1760                   3511                156
  4              1759                   3509                156
  5              1762                   3514                157
  6              1761                   3513                157
  7              1760                   3510                157
  8              1759                   3509                157
  9              1762                   3514                158
 10              1761                   3512                158
 11              1760                   3511                158
 12              1759                   3509                158

我试过了

SELECT A.*
FROM sameanswers AS A
INNER JOIN (SELECT questionid, answerid
        FROM sameanswers
        GROUP BY questionid, answerid
        HAVING COUNT(*) > 1) as B
ON A.questionid = B.questionid AND A.answerid = B.answerid

我的预期输出是有多少用户有相同的选择和多少问题。例如，2个用户在2个问题上有相同的答案。

Answer 1

如果我理解正确，您需要一份有关某人已回答的所有问题的清单，以及使用相同答案回答相同问题的其他人的清单。

使用子查询的粗略方式： -

SELECT A.*, b.others_count
FROM sameanswers AS A
LEFT OUTER JOIN 
(
    SELECT questionid, answerid, COUNT(*) AS others_count
    FROM sameanswers
    WHERE userid != 156
    GROUP BY questionid, answerid
) as B
ON A.questionid = B.questionid AND A.answerid = B.answerid
WHERE A.userid = 156

或使用普通联接： -

SELECT A.id, A.questionid, A.answerid, A.userid, COUNT(B.id)
FROM sameanswers AS A
LEFT OUTER JOIN sameanswers AS B
ON A.questionid = B.questionid AND A.answerid = B.answerid AND A.userid != B.userid
WHERE A.userid = 156
GROUP BY A.id, A.questionid, A.answerid, A.userid;

SQL的小提琴： -

http://www.sqlfiddle.com/#!2/07670/9

编辑 - 这应该为您的新要求得到结果： -

SELECT B.userid, COUNT(B.id) AS match_count
FROM sameanswers AS A
LEFT OUTER JOIN sameanswers AS B
ON A.questionid = B.questionid 
AND A.answerid = B.answerid 
AND A.userid != B.userid
WHERE A.userid = 156
GROUP BY B.userid
ORDER BY match_count DESC LIMIT 1;

我们怎样才能得到多少用户得到答案的相同问题

1 个答案: