Sql join query and select one more column

Question

I have three tables : answers , questions and users and I have joined them all to get the result that I want

SELECT answers.answer_content as answer_content,
       answers.id as answer_id,
       answers.created_at as created_at,
       questions.id as question_id, 
       questions.question_title as question_title, 
       questions.question_slug as question_slug, 
       users.id as user_id, 
       users.name as user_name, 
       users.user_slug as user_slug,
                                  FROM answers
                                          JOIN questions
                                               on questions.id = answers.question_id
                                          JOIN users
                                               on users.id = answers.user_id
                                          WHERE questions.question_active = 1 and 
                                                answers.answer_active = 1

And Now I have one more table named upvote_answers . This table basically stores upvote, downvote for an answer by a user.

if a user has upvoted an answer ie Columns are user_id , answer_id , upvote (1 or 0 - upvote or downvote respectively)

So my question is : I want to get one more column with a boolean result that should show upvoted or downvoted or nothing for each answer for current logged in user

I tried writing the query like this

SELECT answers.answer_content as answer_content,
       answers.id as answer_id,
       answers.created_at as created_at,
       questions.id as question_id, 
       questions.question_title as question_title, 
       questions.question_slug as question_slug, 
       users.id as user_id, 
       users.name as user_name, 
       users.user_slug as user_slug,
       (SELECT count(upvote_answers.answer_id) from upvote_answers, answers WHERE upvote_answers.user_id = 2 and answers.id = upvote_answers.answer_id) as upvotedOrNot
                                  FROM answers
                                          JOIN questions
                                               on questions.id = answers.question_id
                                          JOIN users
                                               on users.id = answers.user_id
                                          WHERE questions.question_active = 1 and 
                                                answers.answer_active = 1

when User loggs in he should be able to see if he has upvoted or downvoted an answer or not.

Answer 1

Considering that a given user can only vote once on any answer, this should do the trick:

SELECT answers.answer_content as answer_content,
       answers.id as answer_id,
       answers.created_at as created_at,
       questions.id as question_id, 
       questions.question_title as question_title, 
       questions.question_slug as question_slug, 
       users.id as user_id, 
       users.name as user_name, 
       users.user_slug as user_slug,
       upvote_answers.upvote as upvote
FROM 
    answers
    JOIN questions on questions.id = answers.question_id
    JOIN users on users.id = answers.user_id
    LEFT JOIN upvote_answers ON
        upvote_answers.answer_id = answers.id AND
        upvote_answers.user_id = answers.user_id
WHERE 
    questions.question_active = 1 and 
    answers.answer_active = 1

The LEFT JOIN clause will yield results if it matches, but will bring NULL values (for its table) if it does not.