Generate Rank (In Database)
(In-Database Processing)
Synopsis
This operator can generate the (dense) rank of each row within the given partition into a new column.Description
The rank of a row is one plus the count of ranks before the given row. The dense rank of a row is one plus the count of distinct ranks before the given row. Note that if no partitioning is defined, the entire data set is sorted, a potentially slow operation for a large data set. For adding a unique ID variable to the data set, you may want to use your database-specific function instead, e.g. ROWNUM for Oracle.
Input
example set input
Output
- example set output
Parameters
- attribute name Name of the attribute.
- partition by Ordered list of the partitioning attributes.
- order by The attributes and sorting directions which should be used to determine the order of the data before the ranking is applied.
- dense rank Dense Rank returns the rank of rows, within the partition of a result set, without any gaps in the ranking.