Enum datafusion_expr::BuiltInWindowFunction

pub enum BuiltInWindowFunction {
    RowNumber,
    Rank,
    DenseRank,
    PercentRank,
    CumeDist,
    Ntile,
    Lag,
    Lead,
    FirstValue,
    LastValue,
    NthValue,
}

A window function built in to DataFusion

Variants

RowNumber

number of the current row within its partition, counting from 1

Rank

rank of the current row with gaps; same as row_number of its first peer

DenseRank

rank of the current row without gaps; this function counts peer groups

PercentRank

relative rank of the current row: (rank - 1) / (total rows - 1)

CumeDist

relative rank of the current row: (number of rows preceding or peer with current row) / (total rows)

Ntile

integer ranging from 1 to the argument value, dividing the partition as equally as possible

Lag

returns value evaluated at the row that is offset rows before the current row within the partition; if there is no such row, instead return default (which must be of the same type as value). Both offset and default are evaluated with respect to the current row. If omitted, offset defaults to 1 and default to null

Lead

returns value evaluated at the row that is offset rows after the current row within the partition; if there is no such row, instead return default (which must be of the same type as value). Both offset and default are evaluated with respect to the current row. If omitted, offset defaults to 1 and default to null

FirstValue

returns value evaluated at the row that is the first row of the window frame

LastValue

returns value evaluated at the row that is the last row of the window frame

NthValue

returns value evaluated at the row that is the nth row of the window frame (counting from 1); null if no such row

Implementations

impl BuiltInWindowFunction

Returns the datatype of the built-in window function

pub fn return_type(&self, input_expr_types: &[DataType]) -> Result<DataType>

pub fn signature(&self) -> Signature

the signatures supported by the built-in window function fun.

Trait Implementations

impl Clone for BuiltInWindowFunction

fn clone(&self) -> BuiltInWindowFunction

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for BuiltInWindowFunction

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for BuiltInWindowFunction

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl FromStr for BuiltInWindowFunction

type Err = DataFusionError

The associated error which can be returned from parsing.

fn from_str(name: &str) -> Result<BuiltInWindowFunction>

Parses a string s to return a value of this type.

impl Hash for BuiltInWindowFunction

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl IntoEnumIterator for BuiltInWindowFunction

type Iterator = BuiltInWindowFunctionIter

fn iter() -> BuiltInWindowFunctionIter

impl PartialEq for BuiltInWindowFunction

fn eq(&self, other: &BuiltInWindowFunction) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Eq for BuiltInWindowFunction

impl StructuralPartialEq for BuiltInWindowFunction