rank ranking window function
Applies to: 
Databricks SQL Databricks Runtime
Returns the rank of a value compared to all values in the partition.
Syntax
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 dense_rank, rank will produce gaps in the ranking sequence.
Unlike row_number, rank does not break ties.
If the order is not unique, the duplicates share the same relative earlier position.
Examples
SQL
> 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