Question

I have two tables, One called StudentCerts containing an email (the primary key) and a certificate, and another called CertReqs, containing a Certificate and Course. Part of the table could look as such:

     StudentCerts:                                 CertReqs:    
Email           Certificate             Certificate          Course
[e-mail]      Programmer            Programmer           CS 101
[e-mail]      English               Programmer           CS 202
[e-mail]            Econ                  Programmer           CS 303
[e-mail]     Programmer            English              ENG 101
                                         English              ENG 102
                                         Econ                 ECON 102
                                         Econ                 ECON 304
                                         Art                  Art 101
                                         Art                  Art 102
                                         Journalism           J 101
                                         Journalism           J 202

what I am trying to do is get all of the certificates that a particular student is not a part of. For example, [e-mail] is enrolled in both the Programmer and English certificate, And I would like to get an SQL statement that would return me all of the certificates in CertReqs that the particular student is not enrolled in. So for this example it should return Econ, Art, and Journalism.
Ive been struggling to get this for some time, so any help would be greatly appreciated!!

Answer 1

SELECT cr.Certificate FROM CertReqs cr
WHERE cr.Certificate NOT IN (
    SELECT sc.Certificate FROM StudentCerts sc
    WHERE sc.Email = '[e-mail]'
);

The query pretty much reads as the requirement: “I want all CertReqs, for which the student is NOT IN”.