while loop to insert data into table in sql - sql-server

Question

declare #temp int,
#temp1 int,
#temp2 int,
#temp3 int,
#temp4 int,
#temp5 int,
#modid int,
#supid int,
#sid varchar(50)
begin tran
select * from StudentSupervisor;
select #temp = count(*) from Students s where s.IsLockedOut = '0' and s.IsGraduated = '0';
select #temp1 = count(*) from staffs st where st.IsLockedOut ='0';
set #temp5 = round(#temp/#temp1,0);
WHILE (select count(*) from students s where s.IsLockedOut ='0' and s.StudentId not in (select ss.StudentId from StudentSupervisor ss where s.StudentId = ss.StudentId and ss.IsApproved = 1)) != 0
BEGIN
select top 1 #sid = s.studentid from students s, StudentSupervisor ss where s.IsLockedOut ='0' and s.StudentId not in (select s.StudentId where s.StudentId = ss.StudentId and ss.IsApproved = 1);
select top 1 #supid = st.Staffid, #modid = st.moderatorid from Staffs st where st.IsLockedOut =0 and Quota <=#temp5;
insert into StudentSupervisor
(StudentId,SupervisorId,ModeratorId,IsApproved)
values
(#sid,#supid,#modid,1)
update Staffs set quota +=1 where staffs.StaffID = #supid;
END
select * from StudentSupervisor;
ROLLBACK tran
Hi all, i am quite stuck on this logic and i did search for solution but i get nothing after overnight work, let me clear with my situation now, first i would like to take count of student that not in studentsupervisor table or in studentsupervisor table but isapproved !=1, then i take the count of staff that quota is not more than total student / total staff,after that i would like to pump student together with staff into studentsupervisor table while they still available.. please let me know what wrong with my dynamic query, thanks

Answer 1

I am having trouble understanding your question. I think your loop condition should be:
WHILE (SELECT COUNT(*) from students WHERE StudentID NOT IN (SELECT StudentID FROM StudentSupervisor WHERE IsAppoved = 1)) <> 0
Depending on what you are trying to do in the loop, it will probably be possible to remove the loop. If you can update your question with more detail on what is happening in the loop and an example I will try to provide a more complete answer.
Update:
In that case I would also update the first line in the loop to:
select top 1 #sid = studentid from students WHERE IsLockedOut = 0 and StudentId NOT IN (SELECT StudentID FROM StudentSupervisor WHERE IsAppoved = 1);
Update2 Table variable option:
declare #temp int,
#temp1 int,
#temp2 int,
#temp5 int,
#PairCount int, --The number of students paired with a staff member.
#modid int,
#supid int,
#StaffQuotaNeed int, --The number of students the staff needs to be paired with to meet quota.
#sid varchar(50)
DECLARE #StaffToPair table
(
StaffID int NOT NULL,
ModeratorID int NOT NULL,
QuotaNeed int NOT NULL --The number of students the staff needs to be paired with to meet quota.
);
DECLARE #StudentsToPair table (StudentID int NOT NULL);
DECLARE #StudentsPaired table (StudentID int NOT NULL);
begin tran
select * from StudentSupervisor;
select #temp = count(*) from Students where IsLockedOut = '0' and IsGraduated = '0';
select #temp1 = count(*) from staffs where IsLockedOut ='0';
set #temp5 = round(#temp/#temp1 + .5, 0); --Round Up
INSERT INTO #StaffToPair (StaffID, ModeratorID, QuotaNeed)
SELECT StaffID, ModeratorID, #temp5 - Quota FROM Staffs WHERE IsLockedOut =0 AND Quota <#temp5;
INSERT INTO #StudentsToPair (StudentID)
SELECT StudentID from students WHERE IsLockedOut = 0 AND StudentId NOT IN (SELECT StudentID FROM StudentSupervisor WHERE IsAppoved = 1);
WHILE (SELECT COUNT(*) from #StudentsToPair) > 0 AND (SELECT COUNT(*) from #StaffToPair) > 0
BEGIN
SELECT TOP 1 #supid = Staffid, #modid = ModeratorID, #StaffQuotaNeed = QuotaNeed FROM #StaffToPair;
INSERT INTO StudentSupervisor (StudentID, SupervisorId, ModeratorId, IsApproved)
OUTPUT INSERTED.StudentID INTO #StudentsPaired(StudentID)
SELECT TOP (#StaffQuotaNeed) StudentID, #supid, #modid, 1 FROM #StudentsToPair;
DELETE FROM #StudentsToPair WHERE StudentID IN (SELECT StudentID FROM #StudentsPaired); --Delete paired students from table variable.
DELETE FROM #StaffToPair WHERE StaffID = #supid; --Delete paired staff from table variable.
SELECT #PairCount = COUNT(*) FROM #StudentsPaired;
UPDATE Staffs set Quota += #PairCount where staffs.StaffID = #supid;
END
select * from StudentSupervisor;
ROLLBACK tran
If the above does not work then please update your question to contain the table schema's so I can test it on my system.