Get all Date of month along with data from table - mysql

Question

I have two tables user_profile and tracked_search. The user_profile table has user details and tracked_search tracks searches made by each user.
Whenever a user makes a search this search entry goes in the tracked_search table. If nothing is searched for a particular date nothing is added in tracked_search.
I need to develop a report where in I need to show on all days of month how many users made searches.
For example:
CREATE TABLE tracked_search (
id int NOT NULL AUTO_INCREMENT PRIMARY KEY,
created DATE,
user_id int NOT NULL
);
INSERT INTO tracked_search(created, user_id) VALUES
('2017-10-01', 1000),
('2017-10-01', 1000),
('2017-10-01', 2000),
('2017-10-01', 3000),
('2017-10-01', 4000),
('2017-10-04', 1000),
('2017-10-04', 2000),
('2017-10-04', 2000),
('2017-10-04', 2000),
('2017-10-04', 2000),
('2017-10-04', 3000),
('2017-10-31', 1000),
('2017-10-31', 2000),
('2017-10-31', 3000),
('2017-10-31', 4000),
('2017-10-31', 5000);
Desired output:
Date user_count
2017-10-01 4
2017-10-02 0
2017-10-03 0
2017-10-04 3
2017-10-05 0
...
2017-10-30 0
2017-10-31 5
I have written following query
SELECT ts.created , count( distinct ts.user_id) FROM tracked_search ts, user_profile u
WHERE ts.created>=(CURDATE()-INTERVAL 1 MONTH) AND u.id = ts.user_id
group by ts.created;
but i get
Date user_count
2017-10-01 4
2017-10-04 3
2017-10-31 5
I need to print all days values if no entry is there for a particular date it should be zero.
I am using MySQL.

Answer 1

By the way, you don't need the join on user_profile.
If you have a dates table with the relevant dates, this is pretty easy:
SELECT dates.day AS `Date`, COUNT(DISTINCT ts.user_id) AS user_count
FROM dates
LEFT OUTER JOIN tracked_search AS ts
ON ts.created = dates.day
GROUP BY dates.day;
Since you probably don't have a dates table and might not want to create and maintain one, you could use one of the solutions for generating the list of dates on the fly. e.g. Get a list of dates between two dates or How to get list of dates between two dates in mysql select query
SELECT dates.day AS `Date`, COUNT(DISTINCT ts.user_id) AS user_count
FROM (
SELECT ADDDATE('1970-01-01', t4.i * 10000 + t3.i * 1000 + t2.i * 100 + t1.i * 10 + t0.i) AS day
FROM (SELECT 0 AS i UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) AS t0,
(SELECT 0 AS i UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) AS t1,
(SELECT 0 AS i UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) AS t2,
(SELECT 0 AS i UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) AS t3,
(SELECT 0 AS i UNION ALL SELECT 1 UNION ALL SELECT 2 UNION ALL SELECT 3 UNION ALL SELECT 4 UNION ALL SELECT 5 UNION ALL SELECT 6 UNION ALL SELECT 7 UNION ALL SELECT 8 UNION ALL SELECT 9) AS t4
) AS dates
LEFT OUTER JOIN tracked_search AS ts
ON ts.created = dates.day
WHERE dates.day >= '2017-10-01'
AND dates.day < '2017-11-01'
GROUP BY dates.day;

Answer 2

You need to write without AND u.id = ts.user_id.
SELECT ts.created , count( distinct ts.user_id) FROM tracked_search ts, user_profile u
WHERE ts.created>=(CURDATE()-INTERVAL 1 MONTH)
group by ts.created;

Answer 3

I was able to solve this using the following logic hope it will help someone
select
t1.attempt_date,
coalesce(SUM(t1.attempt_count+t2.attempt_count), 0) AS attempt_count
from
(
select DATE_FORMAT(a.Date,'%Y/%m/%d') as attempt_date,
'0' as attempt_count
from (
select curdate() - INTERVAL (a.a + (10 * b.a) + (100 * c.a)) DAY as Date
from (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as a
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as b
cross join (select 0 as a union all select 1 union all select 2 union all select 3 union all select 4 union all select 5 union all select 6 union all select 7 union all select 8 union all select 9) as c
) a
where a.Date BETWEEN NOW() - INTERVAL 1 MONTH AND NOW()
)t1
left join
(
SELECT DATE_FORMAT(ts.created,'%Y/%m/%d') AS attempt_date,
count( distinct ts.user_id) AS attempt_count
FROM tracked_search ts, user_profile u
WHERE ts.user_id = u.id and
DATE_SUB(ts.created, INTERVAL 1 DAY) > DATE_SUB(DATE(NOW()), INTERVAL 1 MONTH)
GROUP BY DAY(ts.created) DESC
)t2
on t2.attempt_date = t1.attempt_date
group by DAY(t1.attempt_date)
order by t1.attempt_date desc;