SQL Queries:DATA Aggregation,JOINS (LEFT,RIGHT,INNER,CROSS & FULL OUTER JOIN)

create table exams(student_id integer,subjects varchar(20),marks int); insert into exams values(1,'chemistry',91),(1,'physics',91),(1,'maths',92) ,(2,'chemistry',91),(2,'physics',91),(2,'maths',92) ,(3,'chemistry',9...