Enum datafusion_expr::window_frame::WindowFrameBound

pub enum WindowFrameBound {
    Preceding(ScalarValue),
    CurrentRow,
    Following(ScalarValue),
}

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

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

Variants

Preceding(ScalarValue)

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(ScalarValue)

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 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,
    Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq<WindowFrameBound> for WindowFrameBound

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

type Error = DataFusionError

The type returned in the event of a conversion error.

fn try_from(value: WindowFrameBound) -> Result<Self>

Performs the conversion.

impl Eq for WindowFrameBound

impl StructuralEq for WindowFrameBound

impl StructuralPartialEq for WindowFrameBound