Merge multiple rows in data to show only a single row in the result - sql

Question

I have a stored procedure which takes 1 parameter, an ID number (systudentid).
The procedure returns 3 rows: a student’s academic counselor (AC), financial counselor (FC), and admissions counselor (EC) along with relevant contact information; 3 different people.
Certain students have ACs and FCs who are the same person, but the query will still return 3 rows.
AdvisorType|AdvisorLastName|AdvisorFirstName|(other data)|systaffID
AC DOE JOHN ..... 12345
AC DOE JOHN ..... 12345
EC SMITH JANE ..... 45678
Where in my code can I plug in the logic (and how, I'm a newbie with sql) so that when the systudentid passed to the procedure identifies a student having the same person for both AC and FC, it will display the results this way.
The advisor type is changed to "SSA" and only one of the records for the double-duty counselor is returned.
AdvisorType|AdvisorLastName|AdvisorFirstName|(other data)|SystaffID
SSA DOE JOHN ...... 12345
EC SMITH JANE ...... 45678
Here is my select statement:
SELECT
SyStaffGroup.Descrip AS AdvisorType
,SyStaff.LastName AS AdvisorLastName
,SyStaff.FirstName AS AdvisorFirstName
,SyStaff.Phone AS AdvisorPhone
,SyStaff.Ext AS AdvisorExtention
,SyStaff.eMail AS AdvisorEMail
,SyStaff.SyStaffID AS SyStaffID
FROM SyStaff (NOLOCK)
JOIN SyAdvisorByEnroll (NOLOCK)
ON SyAdvisorByEnroll.SyStaffID = SyStaff.SyStaffID
JOIN SyStaffGroup (NOLOCK)
ON SyStaffGroup.SyStaffGroupID = SyAdvisorByEnroll.SyStaffGroupID
JOIN AdEnroll (NOLOCK)
ON AdEnroll.AdEnrollID = SyAdvisorByEnroll.AdEnrollID
JOIN SyStudent (NOLOCK)
ON AdEnroll.SyStudentID = SyStudent.SyStudentId
WHERE
SyStaff.Active = 1
--AND
--syadvisorbyenroll.adenrollid = (
--SELECT adenrollid from dbo.fn_student_enrollment_activeenrollmentlist (#systudentid)
--)
AND adEnroll.adEnrollID IN (
SELECT adEnrollID FROM dbo.fn_Student_Enrollment_ActiveEnrollmentList(#SyStudentID)
)
AND SyAdvisorByEnroll.AdvisorModule IN ('AD','FA')
AND SyStaffGroup.Descrip IN ('AC - Academic Counselor', 'FC - Finance Counselors', 'EC - Adm. Counselor With Reg')
UNION
SELECT DISTINCT
'Admissions Counselor' AS AdvisorType
,SyStaff.LastName AS AdvisorLastName
,SyStaff.FirstName AS AdvisorFirstName
,SyStaff.Phone AS AdvisorPhone
,SyStaff.Ext AS AdvisorExtention
,SyStaff.eMail AS AdvisorEMail
,SyStaff.SyStaffID AS SyStaffID
FROM systudent
INNER JOIN AmRep ON SyStudent.AMREpID = AmREp.AMREpid
INNER JOIN SyStaff ON SyStaff.SyStaffID = AmRep.AmRepID
WHERE Systudent.SYStudentid = #systudentid
Any hints or suggested methods that I can either try or Google (I've tried searching but results are a lot more useful if I knew what to look for) would be greatly appreciated.

Answer 1

You can add a nested subquery to indicate which students have the same advisor filling multiple positions, and adjust the type selection accordingly. Here are the changed portions of your above query:
SELECT
CASE WHEN (mutiples.SyStaffID IS NOT NULL) THEN 'SSA'
ELSE SyStaffGroup.Descrip END AS AdvisorType
-- other columns omitted
FROM SyStaff (NOLOCK)
JOIN SyAdvisorByEnroll (NOLOCK)
ON SyAdvisorByEnroll.SyStaffID = SyStaff.SyStaffID
LEFT JOIN (
SELECT SyStaffID,AdEnrollID
FROM SyAdvisorByEnroll
GROUP BY SyStaffID,AdEnrollID
HAVING COUNT(DISTINCT SyStaffGroupID) > 1
) multiples
ON multiples.SyStaffID = SyAdvisorByEnroll.SyStaffID
AND multiples.AdEnrollID = SyAdvisorByEnroll.AdEnrollID
-- rest of query omitted
This might have a mistake or two, since you didn't include your table schema. The nested subquery, "multiples", contains all advisor / enrollee pairs where the advisor is in multiple groups. You left join against this and adjust the final type selection to "SSA" if there's a matching entry in the nested subquery.
An important note: as written, this will include two SSA rows for an eligible advisor / enrollee pair. However, the final results will not, because you are using a UNION in this query, which filters out duplicates, even if they're only present in one half of the union. If you change this to UNION ALL or eliminate the UNION entirely, you will need to add DISTINCT to the top of the query, like so:
SELECT DISTINCT CASE WHEN (mutiples.SyStaffID IS NOT NULL) ...