How to add condition in mysql query to count rows?

Question

MySQL

I have such a request

SELECT user_id, dogovor_name, COUNT(*) AS cnt
                    FROM user_dolg
                    WHERE dogovor_name='обыкновенный'
                    GROUP BY user_id

counts clearly, but it is necessary that if no matches are found, put in cnt 0, how to do this?

Answer 1

I wrote on my knee, I need to check ...

SELECT user_id, 'обыкновенный' dogovor_name, SUM(case when dogovor_name='обыкновенный' then 1 else 0 end) AS cnt
                    FROM user_dolg
                    GROUP BY user_id