📋 SQL EXISTS, NOT EXISTS, ANY & ALL Tutorial

🔎 SQL Tutorial: EXISTS, NOT EXISTS, ANY, and ALL

These SQL operators are useful for checking existence and comparing values from subqueries.

📋 Sample Tables

employees

employee_id	name	department_id	salary
1	Arif	101	50000
2	Nasrin	102	60000
3	Rafi	101	55000
4	Ritu	103	45000
5	Faruk	102	62000

departments

department_id	department_name
101	Human Resources
102	Engineering
103	Marketing
104	Finance

1️⃣ EXISTS

Find departments which have at least one employee.

SELECT department_name
FROM departments d
WHERE EXISTS (
  SELECT 1 FROM employees e WHERE e.department_id = d.department_id
);

Output:

department_name
Human Resources
Engineering
Marketing

2️⃣ NOT EXISTS

Find departments which have no employees.

SELECT department_name
FROM departments d
WHERE NOT EXISTS (
  SELECT 1 FROM employees e WHERE e.department_id = d.department_id
);

Output:

department_name
Finance

3️⃣ ANY

Find employees whose salary is greater than any employee in department 101.

SELECT name, salary
FROM employees
WHERE salary > ANY (
  SELECT salary FROM employees WHERE department_id = 101
);

Output:

name	salary
Nasrin	60000
Faruk	62000

4️⃣ ALL

Find employees whose salary is greater than all employees in department 101.

SELECT name, salary
FROM employees
WHERE salary > ALL (
  SELECT salary FROM employees WHERE department_id = 101
);

Output:

name	salary
Faruk	62000

📌 Summary:

• EXISTS: Checks if subquery returns any rows.
• NOT EXISTS: Checks if subquery returns no rows.
• ANY: True if condition holds for any value in subquery.
• ALL: True if condition holds for all values in subquery.

SQL EXISTS tutorial, SQL NOT EXISTS example, SQL ANY operator, SQL ALL operator, Bangladeshi employee data, SQL subquery examples, beginner SQL tutorial, MySQL EXISTS queries