Jaa

dense_rank ranking window function

  • Artikkeli

Applies to: check marked yes Databricks SQL check marked yes Databricks Runtime

Returns the rank of a value compared to all values in the partition.

Syntax

dense_rank()

Arguments

This function takes no arguments.

Returns

An INTEGER.

The OVER clause of the window function must include an ORDER BY clause. Unlike the function rank ranking window function, dense_rank will not produce gaps in the ranking sequence. Unlike row_number ranking window function, dense_rank does not break ties. If the order is not unique the duplicates share the same relative later position.

Examples

> SELECT a,
         b,
         dense_rank() OVER(PARTITION BY a ORDER BY b),
         rank() OVER(PARTITION BY a ORDER BY b),
         row_number() OVER(PARTITION BY a ORDER BY b)
    FROM VALUES ('A1', 2), ('A1', 1), ('A2', 3), ('A1', 1) tab(a, b);
 A1 1   1   1   1
 A1 1   1   1   2
 A1 2   2   3   3
 A2 3   1   1   1