DENSE_RANK
DENSE_RANK computes the rank of each row returned from a query with respect to the other rows, based on the values in the ORDER BY clause.
Syntax
DENSE_RANK () OVER ( [ PARTITION BY expression [, ...] ]
ORDER BY expression [ ASC | DESC ] [ NULLS { FIRST | LAST } [, ...] )
Remarks
• PARTITION BY is optional.
• ORDER BY is required.
• The window clause is not allowed.