How to mention two aggregation functions in the same query? - mysql

Question

I have an sql query to get information from three different tables as following:
select users.username, users.id, users.avatar, users.daily_tahmin, users.alert, f1.comments_no, f2.tahmins_no, f3.monthly_tahmins_no from users LEFT join
(SELECT count(comments) AS comments_no, user_id
FROM comments
Where user_id = 12
) AS f1 on users.id = f1.user_id left join
(
SELECT count(tahmin) AS tahmins_no, user_id
FROM tahminler
Where user_id = 12
) AS f2 on users.id = f2.user_id left join
(
SELECT count(tahmin) AS monthly_tahmins_no, user_id, matches_of_comments.match_id
FROM tahminler
INNER JOIN matches_of_comments on tahminler.match_id = matches_of_comments.match_id
Where user_id = 12 AND (MONTH( STR_TO_DATE( matches_of_comments.match_date, '%d.%m.%Y' ) ) = '01' AND YEAR( STR_TO_DATE( matches_of_comments.match_date, '%d.%m.%Y' ) ) = '2014')
) AS f3 on users.id = f3.user_id
where users.id = 12
and it gives the following result :
+------------+----+----------------+--------------+-------+-------------+------------+--------------------+
| username | id | avatar | daily_tahmin | alert | comments_no | tahmins_no | monthly_tahmins_no |
+------------+----+----------------+--------------+-------+-------------+------------+--------------------+
| cold heart | 12 | 1389002263.jpg | 0 | 0 | 65 | 258 | 10 |
+------------+----+----------------+--------------+-------+-------------+------------+--------------------+
The previous code was not optimized after i do some EXPLIAN and I tried to optimized it and I got the following query:
SELECT m.*,count(comments.id)
FROM comments
JOIN
(SELECT users.username, users.id, users.avatar, users.daily_tahmin, users.alert
FROM users
WHERE id=12)as m ON m.id = comments.user_id
My problem is that I can not get (tahmins_no,monthly_tahmins_no) every time i add them to the query it gives wrong result I can not find a way to add them correctly to the query to be in optimized way?? can I have any advice from anybody here?

Answer 1

Your simplified query is:
select m.*, count(c.id)
from comments c join
users m
on m.id = c.user_id
where m.id = 12
group by m.id;
You should be able to add in the monthly number:
select m.*, count(c.id), f3.*
from comments c join
users m
on m.id = c.user_id join
(select count(tahmin) AS monthly_tahmins_no, user_id, moc.match_id
from tahminler t join
matches_of_comments moc
on t.match_id = moc.match_id
Where user_id = 12 AND
MONTH( STR_TO_DATE( moc.match_date, '%d.%m.%Y' ) ) = 1 AND
YEAR( STR_TO_DATE( moc.match_date, '%d.%m.%Y' ) ) = 2014
) f3
on f3.user_id = m.id
where m.id = 12
group by m.id;
The month() and year() function return numbers, not strings. I don't understand why the field match_date would be stored as a string -- seems like a silly choice for a column whose name contains date.