Display values in gridview based on value of another table

Question

i have two tables:
"subject" table:

dept | sem | subject
EC | 4 | physics
EC | 4 | chemistry
EC | 5 | english
"marks" table:

dept | sem | rollno |name | subject | marks
EC | 4 | 1 | abc | physics | 80 
EC | 4 | 2 | xyz | physics | 95 
EC | 4 | 1 | abc | chemistry| 90 
EC | 4 | 2 | xyz | chemistry| 85 

my expected "output" in the gridview is like:

(the subject names are retrieved from the subject table based on the "sem" values(sem 4-physics,chemistry;sem 5- english and so..)

dept| sem | rollno |name | physics | chemistry | total
EC | 4 | 1 | abc | 80 | 90 | 170
EC | 4 | 2 | xyz | 95 | 85 | 170
when i use a query like:

select rollno,name,marks as physics from marks where subject='physics'
i get it perfectly as my expecatation.,but, i want to display the output in a gridview in asp.net webpage using c# .,so how can do this for multiple column values(physics,chemistry)? I searched many websites,but, still im not having any clear idea.should i acheive my goal using SQL QUERY OR GRIDVIEW FEATURES? if so what features and how? pls help.