SQL

subquery in sql

SELECT column_name
 FROM table_name1
WHERE VALUE IN 
(SELECT column_name
FROM table_name2 
WHERE condition)

SQL Subquery

SELECT *
FROM Customers
WHERE age = (
  SELECT MIN(age)
  FROM Customers
);

what is subquery in sql

SUBQUERY IS NESTED QUERY INSIDE A SELECT, 
INSERT OR UPDATE METHODS. OR INSIDE ANOTHER SUBQUERY

sql subquery

SELECT name, listed_price
FROM paintings
WHERE listed_price > (
    SELECT AVG(listed_price)
    FROM paintings
);

subquery in sql

UPDATE dataflair_emp1 
SET salary=35000
WHERE emp_id  = ( SELECT emp_id
                    FROM dataflair_emp1
                    WHERE post='Sr.Manager');     
select * from dataflair_emp1;

subquery sql

UPDATE Book SET note= 'editore: ' + (SELECT name FROM Publisher WHERE Publisher.ID = Book.publisher)

subquery in sql

DELETE FROM dataflair_emp1
WHERE emp_id IN ( SELECT emp_id
                   FROM dataflair_emp2
                   WHERE age=25);  
select * from dataflair_emp1;

why we use subquery in sql

We use subquery in order to get aggregate value in column without grouping data