Question

I have a query that pulls up questions from one table and answers from another.

SELECT    questions.question,    questions.answers,    (SELECT COUNT(answer) FROM answers WHERE question_id = 1 AND answer = 1            GROUP BY answer) as ans1,    (SELECT COUNT(answer) FROM answers WHERE question_id = 1 AND answer = 2            GROUP BY answer) as ans2  FROM questions  WHERE questions.id = 1 

While this works I don’t like the idea of adding an extra subquery for each answer (questions.answers is a comma-seperated string of potential answers). It’s do-able but I’m sure there must be a better way. The main thing is that different questions have different numbers of answers.

Is there a better way to do this or is this an acceptable way of doing things? I’d imagine multiple subselects in a query could have a (small) performance hit in the future (not that I’m performance testing yet).

If it’s applicable I don’t expect to have more than 5 answers per question.

Answer 1

SELECT q.question, q.answers,   SUM(a.answer = 1) AS ans1,   SUM(a.answer = 2) AS ans2 FROM questions q  LEFT OUTER JOIN answers a ON (q.id = a.question_id) WHERE q.id = 1 GROUP BY q.id;