Adapting two queries - mysql

Question

Hello again community.
I recently received help with the solution to a problem that consisted of List grouped data by month including months in which there are no results
Now I have the same scenario but with the difference that there is a condition to evaluate. I need to adapt this query
select
date_format(a.date_created, '%b') month,
month(a.date_created) pivot,
sum(case when a.state = 'created' then 1 else 0 end) created,
sum(case when a.state = 'notified' then 1 else 0 end) notified,
sum(case when a.state = 'confirmed' then 1 else 0 end) confirmed,
sum(case when a.state = 'approved' then 1 else 0 end) approved,
sum(case when a.state = 'authorized' then 1 else 0 end) authorized,
sum(case when a.state = 'attended' then 1 else 0 end) attended,
sum(case when a.state = 'canceled' then 1 else 0 end) canceled,
count(a.id) as total
from
activities a
inner join
employees e on a.employee_id = e.id
where
e.id = 8
group by 1, 2 order by pivot desc;
To this query
select
s.name month,
s.m pivot,
sum(case when a.state = 'created' then 1 else 0 end) created,
sum(case when a.state = 'notified' then 1 else 0 end) notified,
sum(case when a.state = 'confirmed' then 1 else 0 end) confirmed,
sum(case when a.state = 'approved' then 1 else 0 end) approved,
sum(case when a.state = 'authorized' then 1 else 0 end) authorized,
sum(case when a.state = 'attended' then 1 else 0 end) attended,
sum(case when a.state = 'canceled' then 1 else 0 end) canceled,
count(a.id) as total
from (
SELECT 1 m, 'Jan' AS name
UNION SELECT 2, 'Feb'
UNION SELECT 3, 'Mar'
UNION SELECT 4, 'Apr'
UNION SELECT 5, 'May'
UNION SELECT 6, 'Jun'
UNION SELECT 7, 'Jul'
UNION SELECT 8, 'Aug'
UNION SELECT 9, 'Sep'
UNION SELECT 10, 'Oct'
UNION SELECT 11, 'Nov'
UNION SELECT 12, 'Dec'
) s
LEFT JOIN activities a
ON s.m = month(date_created)
group by 1, 2 order by pivot desc;
I do not know how in the context of the solution that worked in the previous question add the condition
I have tested the following but the months in which there are no results are not listed
select
s.name month,
s.m pivot,
sum(case when a.state = 'created' then 1 else 0 end) created,
sum(case when a.state = 'notified' then 1 else 0 end) notified,
sum(case when a.state = 'confirmed' then 1 else 0 end) confirmed,
sum(case when a.state = 'approved' then 1 else 0 end) approved,
sum(case when a.state = 'authorized' then 1 else 0 end) authorized,
sum(case when a.state = 'attended' then 1 else 0 end) attended,
sum(case when a.state = 'canceled' then 1 else 0 end) canceled,
count(a.id) as total
from (
SELECT 1 m, 'Jan' AS name
UNION SELECT 2, 'Feb'
UNION SELECT 3, 'Mar'
UNION SELECT 4, 'Apr'
UNION SELECT 5, 'May'
UNION SELECT 6, 'Jun'
UNION SELECT 7, 'Jul'
UNION SELECT 8, 'Aug'
UNION SELECT 9, 'Sep'
UNION SELECT 10, 'Oct'
UNION SELECT 11, 'Nov'
UNION SELECT 12, 'Dec'
) s
LEFT JOIN activities a
ON s.m = month(date_created)
inner join employees e on a.employee_id = e.id
group by 1, 2 order by pivot desc;
I share the following sqlfiddle that includes the relationship between employee and activity
I am expecting for the user with id 2 the results should be as follows
Again, thank you very much.

Answer 1

You just had the joins muddled. For the join between activities and employees to be considered as INNER join it has to be enclosed in brackets. Let's know whether it works!
Here is the solution
select
s.name month,
s.m pivot,
sum(case when a.state = 'created' then 1 else 0 end) created,
sum(case when a.state = 'notified' then 1 else 0 end) notified,
sum(case when a.state = 'confirmed' then 1 else 0 end) confirmed,
sum(case when a.state = 'approved' then 1 else 0 end) approved,
sum(case when a.state = 'authorized' then 1 else 0 end) authorized,
sum(case when a.state = 'attended' then 1 else 0 end) attended,
sum(case when a.state = 'canceled' then 1 else 0 end) canceled,
count(a.id) as total
from (
SELECT 1 m, 'Jan' AS name
UNION SELECT 2, 'Feb'
UNION SELECT 3, 'Mar'
UNION SELECT 4, 'Apr'
UNION SELECT 5, 'May'
UNION SELECT 6, 'Jun'
UNION SELECT 7, 'Jul'
UNION SELECT 8, 'Aug'
UNION SELECT 9, 'Sep'
UNION SELECT 10, 'Oct'
UNION SELECT 11, 'Nov'
UNION SELECT 12, 'Dec'
) s
LEFT JOIN ( activities a INNER JOIN employees e
ON a.employee_id = e.id AND e.id = 2)
ON (s.m = month(a.date_created))
group by 1, 2 order by pivot desc;

Answer 2

I think this version does what you want:
select s.name as month, s.m as pivot,
sum(case when a.state = 'created' then 1 else 0 end) created,
sum(case when a.state = 'notified' then 1 else 0 end) notified,
sum(case when a.state = 'confirmed' then 1 else 0 end) confirmed,
sum(case when a.state = 'approved' then 1 else 0 end) approved,
sum(case when a.state = 'authorized' then 1 else 0 end) authorized,
sum(case when a.state = 'attended' then 1 else 0 end) attended,
sum(case when a.state = 'canceled' then 1 else 0 end) canceled,
count(a.id) as total
from (SELECT 1 m, 'Jan' AS name UNION ALL
SELECT 2, 'Feb' UNION ALL
SELECT 3, 'Mar' UNION ALL
SELECT 4, 'Apr' UNION ALL
SELECT 5, 'May' UNION ALL
SELECT 6, 'Jun' UNION ALL
SELECT 7, 'Jul' UNION ALL
SELECT 8, 'Aug' UNION ALL
SELECT 9, 'Sep' UNION ALL
SELECT 10, 'Oct' UNION ALL
SELECT 11, 'Nov' UNION ALL
SELECT 12, 'Dec'
) s LEFT JOIN activities a
ON s.m = month(date_created) left join
employees e
on a.employee_id = e.id AND e.id = 2
group by 1, 2
order by pivot desc;
Here is the SQL Fiddle.
The major change is moving the condition on e.id to the ON clause and changing the second join to a LEFT JOIN. In addition, I changed the UNION to UNION ALL, to eliminate the overhead of removing duplicates.