Question

我有一个像这样的大答案表

person_id|question_id|answer
1|101|6
1|102|2
1|103|5    
2|101|2
2|102|5
2|103|5    
3|101|2
3|102|8
3|103|6    
4|101|2
4|102|8
4|103|6
4|101|6
4|102|2
4|103|5

如何归还人员取决于多个问题的答案？例如，我需要回复回答的人：

6 for question 101 

and 2 for question 102 

and 5 for question 103

查询应返回人1和4

并考虑我需要根据10个问题进行过滤，因此我不需要在桌面上进行10次自我加入：）

Answer 1

您可以使用group by和having：

执行此操作

select person_id
from t
where (question_id, answer) in ( (101, 6), (102, 2), (103, 5) )
group by person_id
having count(distinct question_id) = 3;

请注意，“3”需要与in列表中的问题数量相匹配。

Answer 2

试试这个：

SELECT DISTINCT PersonID
FROM TableName
WHERE 1 = CASE WHEN  question_id = 101 AND Ans=6 THEN 1 
               WHEN  question_id = 102 AND Ans=2 THEN 1 
               WHEN  question_id = 103 AND Ans=5 THEN 1 
          END

Answer 3

SELECT PersonID 
FROM  (
            SELECT PersonID,
            CASE WHEN  question_id = 101 AND Ans=6 THEN 1 
                 WHEN  question_id = 102 AND Ans=2 THEN 1 
                 WHEN  question_id = 103 AND Ans=5 THEN 1 
            END  as [count]
            FROM TableName
            GROUP BY PersonID,question_id,Ans
                                                ) x
WHERE x.[count]=3

返回结果取决于没有自连接的多行的条件

3 个答案: