I have these two tables: COURSE and COURSE_SEQUENCE_REPORT
I am trying to display course number, course name, course prerequisite number and course prerequisite name. The prerequisite ID is a is obtained as a relation to the course ID. If the presequisite ID is 11 then the prerequisite name is Mathematics from the course ID. I was able to come up with this:
SELECT C.COURSE_NUMBER AS "COURSE NUMBER",
C.COURSE_NAME AS "COURSE NAME"
FROM COURSE C JOIN COURSE_SEQUENCE_REPORT CSR
ON CSR.COURSE_ID = C.COURSE_ID
ORDER BY C.COURSE_NUMBER;
...but I am left with the course prerequisite number and name. How do I go about it please? I am confused.
You want two joins:
SELECT C.COURSE_NUMBER AS COURSE_NUMBER,
C.COURSE_NAME AS COURSE_NAME,
CP.COURSE_NUMBER AS PREREQUISITE_NUMBER,
CP.COURSE_NAME AS PREREQUISITE_NAME
FROM COURSE_SEQUENCE_REPORT CSR JOIN
COURSE C
ON CSR.COURSE_ID = C.COURSE_ID JOIN
COURSE CP
ON CSR.PREREQUISITE_ID = CP.COURSE_ID
ORDER BY C.COURSE_NUMBER;
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