How do I 'subtract' sql tables?

Question

Its not really a subtraction I\'m looking for. And I know its not a union or intersection... I have been given a long and complex stored procedure that returns a table of

Answer 1

SELECT roll_number FROM profile WHERE(catagory='Attest and Eat' or catagory='Live and Eat') and status='OK' EXCEPT SELECT roll_number from meal_status  WHERE date='29' AND month='1'

You can try this kind of command to subtract a table from another one.