What does the following window expression do? AVG(salary) OVER (PARTITION BY dept ORDER BY hire_date ROWS BETWEEN 2 PRECEDING AND CURRENT ROW)

Question

SQL Data Analyst — Medium

What does the following window expression do? AVG(salary) OVER (PARTITION BY dept ORDER BY hire_date ROWS BETWEEN 2 PRECEDING AND CURRENT ROW)

Accepted Answer

The window expression AVG(salary) OVER (PARTITION BY dept ORDER BY hire_date ROWS BETWEEN 2 PRECEDING AND CURRENT ROW) calculates a 3-row moving average of salary within each department, based on the hire date order.