Find the missing dates - vba Sql - sql

Question

I am trying to spot which student didn't submit his task and for what date. I want to check for every student whether current or not. I don't mind if the answer is in sql or vba code. More specification below:
Task Table
-------------------------------
SubID |ID | Task | Date
-------------------------------
1 |1 | Dance | 01-01-2014
2 |1 | Sing | 02-01-2014
3 |1 | shout | 05-01-2014
4 |2 | try | 02-01-2014
5 |3 | Okay | 01-01-2014
6 |2 | random| 06-01-2014
8 |4 |Jumping| 01-01-2014
9 |4 | try | 02-01-2014
10 |4 | Piano | 03-01-2014
11 |4 | try | 04-01-2014
12 |4 | guitar| 05-01-2014
13 |4 | try | 06-01-2014
Student table --the Date is in the dd-mm-yyyy format. - also it is a date/time datatype
ID | Name | Current
--------------------
1 | Ron | YES
2 | sqlJ | YES
3 | jque | NO
4 | holy | YES
5 | htdoc| YES
Desired Result:
Who Didn't submit their task between 01-01-2014 and 06-01-2014
ID | Date
---------------
1 | 03-01-2014
1 | 04-01-2014
1 | 06-01-2014
2 | 01-01-2014
2 | 03-01-2014
2 | 04-01-2014
2 | 05-01-2014
3 | 02-01-2014
3 | 03-01-2014
3 | 04-01-2014
3 | 05-01-2014
3 | 06-01-2014
What I have tried:
SELECT w.ID, w.Date, student.[first name], student.[last name], student.[id]
FROM tasktbl AS w
right join student
on w.id = student.[id];
//I was thinking of using a vba-for loop to iterate over the range of date and store it in an array spot every Id that doesn't have a date but it didn't work out quite well.
Any help ranging from pseudo-code to sql-code to vba-code (basically any hint towards my quest) will be appreciated

Answer 1

I used a calendar table which contains one row for each date. Cross joining that table with student, and restricting the date range to your 6 values gave me 30 rows (6 dates times 5 students):
SELECT sub.*
FROM
(
SELECT c.the_date, s.ID
FROM tblCalendar AS c, student AS s
WHERE c.the_date Between #1/1/2014# And #1/6/2014#
) AS sub
Then I used that as a subquery and LEFT JOINed it to tasktbl. So the rows where the "right side" is Null, are those where a student did not complete a task on the date in question.
SELECT sub.ID AS student_id, sub.the_date
FROM
(
SELECT c.the_date, s.ID
FROM tblCalendar AS c, student AS s
WHERE c.the_date Between #1/1/2014# And #1/6/2014#
) AS sub
LEFT JOIN tasktbl AS t
ON (sub.ID = t.ID) AND (sub.the_date = t.Date)
WHERE t.ID Is Null
ORDER BY sub.ID, sub.the_date;

Answer 2

You should be able to do this without any VBA.
select s.id, t.date
from
( --this will populate every possible date, for every student
select distinct s.id
from students s
) s
cross join
(
select distinct t.date
from taskTable t
) t
left join taskTable tt on s.id = tt.id and t.date = tt.date
where tt.date is null
--(optional) order by clause, if needed
Essentially what this is doing is pulling one entry for each possible student (from the "s" table) and one entry for each possible date (from the "t" table) and doing a cross join, which generates a result set with a row containing each possible date for each possible student. By left joining this back to the taskTable (where the taskTable's date field is null) will only return the entries from the cross join table that do not have tasks associated with them.
I would also recommend you re-think the design of the TaskTable, and instead of tracking only completed tasks, track all tasks and add a field "completed" which stores if the task has been completed (Yes) or not (No).