Window Functions
Window function syntax has been added. A window function is defined "over" a group of rows (a window) from a query. It produces a result value for each input row, where the value is computed according to the records in the current window.
Such syntax is required with analytical functions and can also be used with aggregate functions. The following analytical functions are supported: RANK, DENSE_RANK, PERCENT_RANK, NTILE, and ROW_NUMBER.
For details, see the SQL Reference Guide.