Question

I’m stuck with a homework..

How can I from this table check what cID, sID = ’03’ are taking? And with that, checking other sID that got the same cID as sID = ’03’ and select it out?

sID    cID      year     grades
--------------------------------
01    L21D   1997   4
01    L24D   1998   2
01    L32D   1998   3
02    L21D   1998   3
02    L32D   1998   4
03    L32D   1998   

This is what I want to select:

sID   cID 
-------------
01   L32D 
02   L32D 
03   L32D 

I’ve tried different combinations, but none have given what I wanted. Maybe I’m too tired for the moment.

For example I tried this:

 


SELECT sID 
FROM studentcourse 
WHERE sID = 
( 
SELECT cID 
FROM studentcourse 
WHERE sID = '03'
)

BR, Jay

Answer 1

Classes that sID = ’03’ is taking:

Select cID from StudentsInClasses where sID = '03'

Students who at some time took the same class as sID = ’03’ (including sID = ’03’):

Select 
    sID
From
    StudentsInClasses
Where
    cID in (Select cID from StudentsInClasses where sID = '03')