UPDATE Std_Marks
set SchoolID=t.schoolid
from Students t,Std_Marks s
where t.ID=s.StudentID

UPDATE Std_Marks
set ClassID=t.ClassID
from Students t,Std_Marks s
where t.ID=s.StudentID

UPDATE Std_Marks
set SectionID=t.SectionID
from Students t,Std_Marks s
where t.ID=s.StudentID



UPDATE Std_Marks
SET includedInAvg=t.includedInAvg
FROM Section_Subject t,Std_Marks s
WHERE t.SchoolID=s.SchoolID and t.ClassID=s.ClassID
and t.SectionID=s.SectionID and t.SubjectId=s.SubjectID