Enum datafusion_expr::window_frame::WindowFrameBound

pub enum WindowFrameBound {
    Preceding(Option<u64>),
    CurrentRow,
    Following(Option<u64>),
}

There are five ways to describe starting and ending frame boundaries:

1. UNBOUNDED PRECEDING
2. PRECEDING
3. CURRENT ROW
4. FOLLOWING
5. UNBOUNDED FOLLOWING

in this implementation we’ll only allow to be u64 (i.e. no dynamic boundary)

Variants

Preceding(Option<u64>)

1. UNBOUNDED PRECEDING The frame boundary is the first row in the partition.

2. PRECEDING must be a non-negative constant numeric expression. The boundary is a row that is “units” prior to the current row.

CurrentRow

3. The current row.

For RANGE and GROUPS frame types, peers of the current row are also included in the frame, unless specifically excluded by the EXCLUDE clause. This is true regardless of whether CURRENT ROW is used as the starting or ending frame boundary.

Following(Option<u64>)

4. This is the same as “ PRECEDING” except that the boundary is units after the current rather than before the current row.

5. UNBOUNDED FOLLOWING The frame boundary is the last row in the partition.

Trait Implementations

impl Clone for WindowFrameBound

fn clone(&self) -> WindowFrameBound

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for WindowFrameBound

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

Formats the value using the given formatter.

impl Display for WindowFrameBound

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

Formats the value using the given formatter.

impl From<WindowFrameBound> for WindowFrameBound

fn from(value: WindowFrameBound) -> Self

Converts to this type from the input type.

impl Hash for WindowFrameBound

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, 

Feeds a slice of this type into the given Hasher.

impl Ord for WindowFrameBound

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self where
    Self: PartialOrd<Self>, 

Restrict a value to a certain interval.

impl PartialEq<WindowFrameBound> for WindowFrameBound

fn eq(&self, other: &Self) -> 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 PartialOrd<WindowFrameBound> for WindowFrameBound

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

This method tests less than (for self and other) and is used by the < operator.

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

This method tests less than or equal to (for self and other) and is used by the <= operator.

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

This method tests greater than (for self and other) and is used by the > operator.

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

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for WindowFrameBound

impl Eq for WindowFrameBound

impl StructuralEq for WindowFrameBound