SQL

nested query

select E.ename from employee E where E.eid IN (select S.eid from salary S where S.regno=103);

nested query

create table student(id number(10), name varchar2(20),classID number(10), marks varchar2(20));
Insert into student values(1,'pinky',3,2.4);
Insert into student values(2,'bob',3,1.44);
Insert into student values(3,'Jam',1,3.24);
Insert into student values(4,'lucky',2,2.67);
Insert into student values(5,'ram',2,4.56);
select * from student;

nested query with all examples

SELECT
  artists.first_name,
  artists.last_name,
  artist_sales.sales
FROM artists
JOIN (
    SELECT artist_id, SUM(sales_price) AS sales
    FROM sales
    GROUP BY artist_id
  ) AS artist_sales
  ON artists.id = artist_sales.artist_id;