Mysql - Finding missing dates with multiple join tables - mysql

Question

I need some help writing a mysql query. I need to find all missed reports for a given date range for a specific business id / project id.
Basically, for a given business id, I need to know the name of the project and all dates that a report is either missing or not marked as completed.
I am using the calendar table trick (as described here and here) to find the missing report dates, but I am having problems joining the projects table to find the associated project / business that a report was missed for.
I basically need a result set that will give me data similar to this:
+------------+-----------+--------------+
| project_id | name | missing_date |
+------------+-----------+--------------+
| 1 | Project 1 | 2014-01-01 |
| 1 | Project 1 | 2014-01-03 |
| 1 | Project 1 | 2014-01-04 |
| 1 | Project 1 | 2014-01-07 |
| 1 | Project 1 | 2014-01-09 |
| 2 | Project 2 | 2014-01-02 |
| 2 | Project 2 | 2014-01-03 |
| 2 | Project 2 | 2014-01-04 |
+------------+-----------+--------------+
Here is my schema:
projects table:
+----------------+------------------+------+-----+-------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------------+------------------+------+-----+-------------------+----------------+
| project_id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| business_id | int(10) unsigned | NO | MUL | NULL | |
| name | tinytext | YES | | NULL | |
+----------------+------------------+------+-----+-------------------+----------------+
reports table:
+---------------------+------------------+------+-----+-------------------+----------------+
| Field | Type | Null | Key | Default | Extra |
+---------------------+------------------+------+-----+-------------------+----------------+
| report_id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| project_id | int(10) unsigned | NO | MUL | NULL | |
| report_date | date | NO | MUL | NULL | |
| completed | bit(1) | NO | | b'0' | |
+---------------------+------------------+------+-----+-------------------+----------------+
calendar table:
+--------------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------+-------------+------+-----+---------+-------+
| dt | date | NO | PRI | NULL | |
| month_name | varchar(9) | YES | | NULL | |
| day_name | varchar(9) | YES | | NULL | |
| y | smallint(6) | YES | | NULL | |
| q | tinyint(4) | YES | | NULL | |
| m | tinyint(4) | YES | | NULL | |
| d | tinyint(4) | YES | | NULL | |
| dw | tinyint(4) | YES | | NULL | |
| w | tinyint(4) | YES | | NULL | |
| is_weekday | bit(1) | YES | | NULL | |
| is_holiday | bit(1) | YES | | NULL | |
| holiday_desc | varchar(32) | YES | | NULL | |
+--------------+-------------+------+-----+---------+-------+
The following query below works to return a list of incompleted reports, but I still need to fill the gaps in with the dates where there is no report record at all.
select
p.project_id,
p.name,
c.dt as missing_date,
r.completed
from reports r
join projects p on (r.project_id = p.project_id)
right join calendar c on (c.dt = r.report_date)
where c.dt >= '2014-02-01'
and c.dt <= '2014-02-10'
-- and r.report_date is null /** THE RESULT SET IS EMPTY IF I UNCOMMENT THIS **/
and r.completed = false
and c.is_holiday = false
and c.is_weekday = true
and p.business_id = 1001
order by p.project_id, r.report_date, c.dt;
Any help would be much appreciated!

Answer 1

I read the links you have provided and this method of storage for dates is great.
any way in your query you used:
right join calendar c on (c.dt = r.report_date)
but I don't see any report_date in your report table.
I suggest you check it if the problem is because of it ,since apart from that your query seems to work properly.

Answer 2

Ok, I finally got it to work. It's a fairly complicated query that requires an inner join on the projects table but I don't know a better way to do it - I'm a Java guy who relies on hibernate way too much these days to build my queries :). If anyone has a more efficient solution I am all ears!
The final query:
select
p.project_id,
p.name,
c.dt as missing_date,
r.report_date,
r.completed
from calendar c
inner join (
select
p1.project_id,
p1.name
from projects p1
where p1.project_id = 1005
-- where p1.business_id = 1001 /** OR USE THE BUSINESS ID **/
) p on c.dt between '2014-02-01' and '2014-02-28'
left join reports r on r.report_date = c.dt
and r.project_id = p.project_id
and r.completed = false
where (r.report_date is null or r.completed = false)
and c.is_holiday = false
and c.is_weekday = true
order by p.project_id, c.dt;
Produces the correct results:
+------------+--------------+--------------+-------------+-----------+
| project_id | name | missing_date | report_date | completed |
+------------+--------------+--------------+-------------+-----------+
| 1005 | Project 1005 | 2014-02-03 | 2014-02-03 | 0 |
| 1005 | Project 1005 | 2014-02-04 | 2014-02-04 | 0 |
| 1005 | Project 1005 | 2014-02-05 | NULL | NULL |
| 1005 | Project 1005 | 2014-02-06 | 2014-02-06 | 0 |
| 1005 | Project 1005 | 2014-02-07 | NULL | NULL |
| 1005 | Project 1005 | 2014-02-10 | 2014-02-10 | 0 |
| 1005 | Project 1005 | 2014-02-11 | 2014-02-11 | 0 |
| 1005 | Project 1005 | 2014-02-12 | 2014-02-12 | 0 |
| 1005 | Project 1005 | 2014-02-13 | NULL | NULL |
| 1005 | Project 1005 | 2014-02-14 | NULL | NULL |
| 1005 | Project 1005 | 2014-02-18 | NULL | NULL |
| 1005 | Project 1005 | 2014-02-19 | NULL | NULL |
| 1005 | Project 1005 | 2014-02-20 | 2014-02-20 | 0 |
| 1005 | Project 1005 | 2014-02-21 | 2014-02-21 | 0 |
| 1005 | Project 1005 | 2014-02-24 | 2014-02-24 | 0 |
| 1005 | Project 1005 | 2014-02-25 | 2014-02-25 | 0 |
| 1005 | Project 1005 | 2014-02-26 | NULL | NULL |
| 1005 | Project 1005 | 2014-02-27 | NULL | NULL |
| 1005 | Project 1005 | 2014-02-28 | NULL | NULL |
+------------+--------------+--------------+-------------+-----------+
Thanks for the help guys and gals!