Format output in SQL so that multiple values of column b are associated with one value of column a
This is my select statement:
SELECT lastName + ',' + firstName as Name,
classNumber
FROM STUDENT
RIGHT JOIN ENROLL ON Enroll.stuid = Student.stuid
and the output:
name classnumber
--------------------------
Smith,Tom ART103A
Smith,Tom HST205A
Chin,Ann ART103A
Chin,Ann CSC201A
Chin,Ann MTH103A
McCarthy,Owen ART103A
McCarthy,Owen MTH103C
Rivera,Jane CSC201A 开发者_如何学Python
Rivera,Jane MTH101B
I would like it so that each name only appears in the first column once. Any help or idea greatly appreciated.
As the rows are all independent from each other, no row can know if it's the first one.
What you could do is to GROUP BY Name and put all the classNumbers together in a list like this:
SELECT lastName + ',' + firstName AS Name,
GROUP_CONCAT(classNumber SEPARATOR '\n') AS classNumbers
FROM student
RIGHT JOIN Enroll ON (Student.stuid = Enroll.stuid)
GROUP BY Name
if only one class will appear.
SELECT lastName + ',' + firstName as Name, classNumber
FROM STUDENT
RIGHT JOIN
(select Student.stuid as stuid, min(classNumber) as ClassNumber
from ENROLL Enroll inner Join Student
ON (Student.stuid = Enroll.stuid) group by Student.stuid) AS NewEnrol
ON NewEnroll.stuid = Student.stuid
Or
SELECT lastName + ',' + firstName as Name,Min(classNumber)
FROM STUDENT
RIGHT JOIN ENROLL ON Enroll.stuid = Student.stuid
Group By lastname+','+firstname
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