What is the difference between ROW_NUMBER(), RANK(), and DENSE_RANK()?

All three assign numbers to rows within a window, but handle ties differently. ROW_NUMBER(): always unique — assigns sequential 1,2,3... even for tied values. Arbitrary which tie gets lower number (depends on physical order or secondary sort). RANK(): assigns same rank to ties, then SKIPS the next number(s): 1,1,3,4. DENSE_RANK(): assigns same rank to ties but does NOT skip: 1,1,2,3. Example with