PERCENTILE ( [ DISTINCT  ALL ] 'value_expression', percentile [, { LINEAR  LOW  HIGH  NEAREST  MIDPOINT } ] )
Syntax Elements
 ALL
 All nonnull value_expressions, including duplicates, in the computation.
 DISTINCT
 Excludes duplicates specified by value_expression from the computation.
 value_expression
 A literal or column expression for which a set of aggregate functions are computed for the series.
The value_expression cannot be a reference to a view column derived from a function, and cannot contain any ordered analytical or aggregate functions.
 percentile
 A Teradata literal float value that represents the desired percentile.
 LINEAR

Use linear interpolation to interpolate the result value when the desired result lies between two data points.
This parameter is not casesensitive.
 LOW

Use a low value interpolation scheme to interpolate the result value when the desired result lies between two data points.
This parameter is not casesensitive.
 HIGH
 Use a high value interpolation scheme to interpolate the result value when the desired result lies between two data points.
 NEAREST
 Use a nearest value interpolation scheme to interpolate the result value when the desired result lies between two data points.
 MIDPOINT
 Use a midpoint interpolation scheme to interpolate the result value when the desired result lies between two data points.