SQL查询返回符合条件的多行

Question

I have a survey system which the following questionanswer table

questionId personId response
1             a       red
2             a       blue
3             a       green
4             a       black
1             b       red
2             b       blue
3             b       green
4             b       black

I need to construct a query for a search form allowing users to pick the question and the response to be returned. ie the user may pick question 1 answer = red and question 3 and answer green

I have to return those personId 's that match that criteria (in the above table it would return a and b)

psuedo: select from questionanswer table all personId's where question=1 && answer=red AND those personId's where question=3 and answer was green

This code would run after the administrator selects 'search' returning back distinct a and b personId's

(seems simple but i must be missing something?)

Answer 1

How are you passing in the QuestionIds and Responses? Let's assume you eventually get them into a table variable:

    DECLARE @Search TABLE 
    ( questionId int, 
      response varchar(30) ) 

Then your SQL then becomes:

    SELECT q.personID
    FROM questionanswertable AS q
    INNER JOIN @Search AS s
    ON s.questionId = q.questionId
       AND s.response = q.response
    GROUP BY q.personID
    HAVING COUNT(1) = (SELECT COUNT(1) FROM @Search)

Answer 2

SELECT DISTINCT personID
FROM questionanswertable 
WHERE (questionID = 1 AND response = 'red')
OR (questionID = 3 AND response = 'green')

Answer 3

SELECT DISTINCT personID
FROM questionanswertable 
WHERE questionID = 3 AND response = 'green' AND personID in (
    SELECT DISTINCT personID
    FROM questionanswertable
    WHERE (questionID = 1 AND response = 'red'))

Answer 4

SELECT DISTINCT personId
FROM questionanswer
WHERE questionId IN(SELECT questionId FROM questionanswer WHERE questionId = 1 AND response = 'red')
AND questionId IN(SELECT questionId FROM questionanswer WHERE questionId = 3 AND response = 'green')