Question

Here is my current query:

SELECT sac.cred, s.status, (SELECT NVL (csl.census_dates, tl.census_dates) 
                                         FROM  schema.sections cs,  schema.sections_ls csl,  schema.terms tl 
                                        WHERE cs.course_sections_id = csl.course_sections_id(+)AND csl.pos(+) = 1 AND cs.term = tl.terms_id 
                                          AND tl.pos = 1 AND cs.course_sections_id = cs2.course_sections_id AND ROWNUM = 1)AS censusDate, 
                                      (SELECT NVL (p.ssn, 'xxx-xx-xxxx') FROM   schema.person p 
                                        WHERE p.id = sac.person_id) AS ssn, 
                                       //schema.person_name(sac.person_id, 'FML') as fml, 
                                       //schema.person_name(sac.person_id, 'LF') as lf 
                                 FROM  schema.student_acad_cred sac JOIN  schema.statuses s 
                                   ON s.student_acad_cred_id = sac.student_acad_cred_id 
                                 JOIN  schema.terms tl ON sac.term = tl.terms_id 
                                 JOIN  schema.student_course_sec scs ON sac.student_course_sec = scs.student_course_sec_id 
                                 JOIN  schema.course_sections cs2 ON scs.course_section = cs2.course_sections_id 
                                 JOIN  schema.terms t ON tl.terms_id = t.terms_id 
                                WHERE sac.person_id = '1111111111' 
                                  AND (s.status IN ('A', 'N') OR (s.status = 'D' AND final_grade IS NOT NULL)) 
                                  AND s.pos = '1'AND tl.pos = '1' AND tl.terms_id = 'spring'; 

And here are the results:

cred      status   currentDate   censusDate     ssn
====      ======   ===========   ==========     ===
  3         N       11/16/2011   12/15/2011      xxx-xx-xxxx
  4         N       11/16/2011   12/15/2011      xxx-xx-xxxx
  3         N       11/16/2011   12/15/2011      xxx-xx-xxxx
  4         N       11/16/2011   12/15/2011      xxx-xx-xxxx
  1         N       11/16/2011   12/15/2011      xxx-xx-xxxx

Okay, what I am trying to do is use sum() (or some other function) to add up all the credit hours that are pulled. So in this instance the sum of all cred hours would be ’15’. Is there a way to do this in query? Ideally I would want something like this:

cred      status   currentDate   censusDate     ssn
====      ======   ===========   ==========     ===
 15         N       11/16/2011   12/15/2011      xxx-xx-xxxx

Answer 1

The way to do this is to GROUP BY all of your other columns. Since you can’t group by aliased columns directly (in Oracle and most RDMBSes), you have to wrap the whole thing in another query and do the grouping there.

SELECT SUM(cred), status, censusDate, ssn 
FROM
    (SELECT sac.cred, s.status, 
          (SELECT NVL (csl.census_dates, tl.census_dates) 
             FROM  schema.sections cs,  schema.sections_ls csl,  schema.terms tl 
            WHERE cs.course_sections_id = csl.course_sections_id(+)AND csl.pos(+) = 1 AND cs.term = tl.terms_id 
              AND tl.pos = 1 AND cs.course_sections_id = cs2.course_sections_id AND ROWNUM = 1)AS censusDate, 
          (SELECT NVL (p.ssn, 'xxx-xx-xxxx') FROM   schema.person p 
            WHERE p.id = sac.person_id) AS ssn, 
           //schema.person_name(sac.person_id, 'FML') as fml, 
           //schema.person_name(sac.person_id, 'LF') as lf 
     FROM  schema.student_acad_cred sac JOIN  schema.statuses s 
       ON s.student_acad_cred_id = sac.student_acad_cred_id 
     JOIN  schema.terms tl ON sac.term = tl.terms_id 
     JOIN  schema.student_course_sec scs ON sac.student_course_sec = scs.student_course_sec_id 
     JOIN  schema.course_sections cs2 ON scs.course_section = cs2.course_sections_id 
     JOIN  schema.terms t ON tl.terms_id = t.terms_id 
    WHERE sac.person_id = '1111111111' 
      AND (s.status IN ('A', 'N') OR (s.status = 'D' AND final_grade IS NOT NULL)) 
      AND s.pos = '1'AND tl.pos = '1' AND tl.terms_id = 'spring')
GROUP BY status, censusDate, ssn;

This looks ugly, but doesn’t actually have a horrible performance impact.