Question

I want to run a query that selects the latest question a user hasn’t answered from 2 separate tables. This is what I came up with:

SELECT Q.question_id, Q.question, S.user_id, S.question_id 
FROM questions Q inner join answers S on Q.question_id=S.question_id 
WHERE S.user_id != '$userID'

This indeed does filter out the rows where the user has answered a specific question but unfortunately if another user answers the same question it still returns that question. I want to eliminate the question being returned all together if the user hasn’t answered.

Suggestions/ideas are welcome, thanks.

Answer 1

“Select all questions which have not been answered by $userId“:

SELECT Q.question_id, Q.question
FROM questions Q 
WHERE 
    Q.question_id NOT IN (
         /* Select all questions's ids, which have been answered by $userId */
         SELECT `question_id` 
         FROM `answer` 
         WHERE `answer`.`user_id` = '$userId'
    )