Question

I have a mysql DB with two tables:

• messages
• message_answers

I’d like to fetch all messages and the number of answers for each of them, like:

• first message (10 answers)
• second message (5 answers)

Is it possible with a single sql query ?

I tried a query and a subquery for the count, but I don’t know how to have the current id from the main query to make the “WHERE” restriction on the subquery (like: “message_answers.message_id = messages.id”).

Thank you,
Sébastien

Answer 1

SELECT m.message, COUNT(ma.answer_id) AS AnswerCount
    FROM messages m
        LEFT JOIN message_answers ma
            ON m.id = ma.message_id
    GROUP BY m.message