Struct StandardWindowExpr

pub struct StandardWindowExpr { /* private fields */ }

A window expr that takes the form of a StandardWindowFunctionExpr.

Implementations

impl StandardWindowExpr

pub fn new( expr: Arc<dyn StandardWindowFunctionExpr>, partition_by: &[Arc<dyn PhysicalExpr>], order_by: &LexOrdering, window_frame: Arc<WindowFrame>, ) -> Self

create a new standard window function expression

pub fn get_standard_func_expr(&self) -> &Arc<dyn StandardWindowFunctionExpr>

Get StandardWindowFunction expr of StandardWindowExpr

pub fn add_equal_orderings(&self, eq_properties: &mut EquivalenceProperties)

Adds any equivalent orderings generated by self.expr to builder.

If self.expr doesn’t have an ordering, ordering equivalence properties are not updated. Otherwise, ordering equivalence properties are updated by the ordering of self.expr.

Trait Implementations

impl Debug for StandardWindowExpr

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

Formats the value using the given formatter.

impl WindowExpr for StandardWindowExpr

fn as_any(&self) -> &dyn Any

Return a reference to Any that can be used for downcasting

fn evaluate_stateful( &self, partition_batches: &PartitionBatches, window_agg_state: &mut PartitionWindowAggStates, ) -> Result<()>

Evaluate the window function against the batch. This function facilitates stateful, bounded-memory implementations.

fn name(&self) -> &str

Human readable name such as "MIN(c2)" or "RANK()". The default implementation returns placeholder text.

fn field(&self) -> Result<Field>

The field of the final result of this window function.

fn expressions(&self) -> Vec<Arc<dyn PhysicalExpr>>

Expressions that are passed to the WindowAccumulator. Functions which take a single input argument, such as sum, return a single datafusion_expr::expr::Expr, others (e.g. cov) return many.

fn partition_by(&self) -> &[Arc<dyn PhysicalExpr>]

Expressions that’s from the window function’s partition by clause, empty if absent

fn order_by(&self) -> &LexOrdering

Expressions that’s from the window function’s order by clause, empty if absent

fn evaluate(&self, batch: &RecordBatch) -> Result<ArrayRef>

Evaluate the window function values against the batch

fn get_window_frame(&self) -> &Arc<WindowFrame>

Get the window frame of this WindowExpr.

fn get_reverse_expr(&self) -> Option<Arc<dyn WindowExpr>>

Get the reverse expression of this WindowExpr.

fn uses_bounded_memory(&self) -> bool

Return a flag indicating whether this WindowExpr can run with bounded memory.

fn evaluate_args(&self, batch: &RecordBatch) -> Result<Vec<ArrayRef>>

Evaluate the window function arguments against the batch and return array ref, normally the resulting Vec is a single element one.

fn order_by_columns(&self, batch: &RecordBatch) -> Result<Vec<SortColumn>>

Get order by columns, empty if absent

fn all_expressions(&self) -> WindowPhysicalExpressions

Returns all expressions used in the WindowExpr. These expressions are (1) function arguments, (2) partition by expressions, (3) order by expressions.

fn with_new_expressions( &self, _args: Vec<Arc<dyn PhysicalExpr>>, _partition_bys: Vec<Arc<dyn PhysicalExpr>>, _order_by_exprs: Vec<Arc<dyn PhysicalExpr>>, ) -> Option<Arc<dyn WindowExpr>>

Rewrites WindowExpr, with new expressions given. The argument should be consistent with the return value of the WindowExpr::all_expressions method. Returns Some(Arc<dyn WindowExpr>) if re-write is supported, otherwise returns None.