Kuidas töötasid analüütilised funktsioonid (akenfunktsioonid)?

Analytical functions (window functions) allow performing calculations over sets of rows related to the current row, without grouping data. For example, you can calculate a moving sum, ranking, or average within data sections.

Example of usage in SQL:

SELECT
  employee_id,
  department_id,
  salary,
  RANK() OVER (PARTITION BY department_id ORDER BY salary DESC) AS salary_rank
FROM employees;

Here, for each employee, the salary rank within their department is calculated. I used window functions for data analysis, simplifying complex queries and improving performance by avoiding subqueries and additional joins.