PARTITION BY (EN)

Definition

PARTITION BY is a clause in window functions that divides records into logical groups within which calculations are performed. It determines the scope of the 'window' on which a window function operates. The correct use of PARTITION BY is crucial for the expected results of window functions such as rankings or cumulative sums.

Example

• Typically used together with ORDER BY and window functions like ROW_NUMBER(), RANK(), DENSE_RANK()
• Related to: OVER(), ORDER BY, Window Functions
• Example usage: PARTITION BY department ORDER BY hire_date divides data by departments and sorts within each department by hire date