PostgreSql(Aggregative Functions)

Aggregative Function: Aggregate functions perform calculations on multiple rows and return a single result. They’re essential for: Summarizing data (e.g., total salary, average marks) Analyzing trends (e.g., highest sales, number of employees per department) Filtering grouped results using HAVING #Common SQL Aggregate Functions: SELECT SUM ( salary ) FROM Employee ; SELECT COUNT ( * ) FROM Employee ; SELECT MAX ( salary ) FROM Employee ; SELECT MIN ( salary ) FROM Employee ; Using Aggregate Functions with GROUP BY: SELECT dept_id , AVG ( salary ) FROM Employee GROUP BY dept_id ; Filtering Groups with HAVING SELECT dept_id , COUNT ( * ) AS emp_count FROM Employee GROUP BY dept_id HAVING COUNT ( * ) > 5 ; Shows only departments with more than 5 employees. Bye.. bye..