DENSE_RANK()
Returns the rank of rows within a result set, without any gaps in the ranking. If column on which dense_rank() is calculated has duplicate value then result will have same rank.
i.e:
![Dens Rank Use in Sql]()
PARTITION BY
Divides the query result set into partitions. The window function is applied to each partition separately and computation restarts for each partition.
![Partition By in Sql]()
Due to Partition by cluase result set is devided by specified column. As in above result set data divided by department and dense_rank is limited to distinct department rows.
- Select Top 3 salary records from table
![Selecting Top 3 Rows]()
In above query department wise top 3 salaried employee selected.
- Select nth department wise highest salary from result set
![Selecting nth Row]()