Question

This is my data

unitCode stunum assNo   subStatus 
SIT111  1000    1   Yes
SIT111  1000    2   No
SIT111  3000    1   No

How do i generate only results with ONLY a ‘No’

eg: Only student 3000 should come up. Since that person has not handed in ANY assignments. ?

Answer 1

You can use the following statement:

select
    *
from
(
    select
        unitCode,
        stunum,
        sum(case when subStatus = 'Yes' then 1 else 0 end) as CountYes,
        sum(case when subStatus = 'No' then 1 else 0 end) as CountNo
    from
        students
    group by
        unitCode, stunum
) as student
inner join student_details
    on student.stunum = student_details.stunum
where
    CountNo > 0 and CountYes = 0;