Struct TryCastExpr 

pub struct TryCastExpr {
    expr: Arc<dyn PhysicalExpr>,
    cast_type: DataType,
}

TRY_CAST expression casts an expression to a specific data type and returns NULL on invalid cast

Fields

expr: Arc<dyn PhysicalExpr>

cast_type: DataType

Implementations

impl TryCastExpr

pub fn new(expr: Arc<dyn PhysicalExpr>, cast_type: DataType) -> TryCastExpr

Create a new CastExpr

pub fn expr(&self) -> &Arc<dyn PhysicalExpr>

The expression to cast

pub fn cast_type(&self) -> &DataType

The data type to cast to

Trait Implementations

impl Debug for TryCastExpr

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

Formats the value using the given formatter.

impl Display for TryCastExpr

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

Formats the value using the given formatter.

impl Hash for TryCastExpr

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

where H: Hasher,

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 for TryCastExpr

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

Tests for self and other values to be equal, and is used by ==.

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

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

impl PhysicalExpr for TryCastExpr

fn as_any(&self) -> &(dyn Any + 'static)

Return a reference to Any that can be used for downcasting

fn data_type(&self, _input_schema: &Schema) -> Result<DataType, DataFusionError>

Get the data type of this expression, given the schema of the input

fn nullable(&self, _input_schema: &Schema) -> Result<bool, DataFusionError>

Determine whether this expression is nullable, given the schema of the input

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

Evaluate an expression against a RecordBatch

fn return_field( &self, input_schema: &Schema, ) -> Result<Arc<Field>, DataFusionError>

The output field associated with this expression

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

Get a list of child PhysicalExpr that provide the input for this expr.

fn with_new_children( self: Arc<TryCastExpr>, children: Vec<Arc<dyn PhysicalExpr>>, ) -> Result<Arc<dyn PhysicalExpr>, DataFusionError>

Returns a new PhysicalExpr where all children were replaced by new exprs.

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

Format this PhysicalExpr in nice human readable “SQL” format

fn evaluate_selection( &self, batch: &RecordBatch, selection: &BooleanArray, ) -> Result<ColumnarValue, DataFusionError>

Evaluate an expression against a RecordBatch after first applying a validity array

fn evaluate_bounds( &self, _children: &[&Interval], ) -> Result<Interval, DataFusionError>

Computes the output interval for the expression, given the input intervals.

fn propagate_constraints( &self, _interval: &Interval, _children: &[&Interval], ) -> Result<Option<Vec<Interval>>, DataFusionError>

Updates bounds for child expressions, given a known interval for this expression.

fn evaluate_statistics( &self, children: &[&Distribution], ) -> Result<Distribution, DataFusionError>

Computes the output statistics for the expression, given the input statistics.

fn propagate_statistics( &self, parent: &Distribution, children: &[&Distribution], ) -> Result<Option<Vec<Distribution>>, DataFusionError>

Updates children statistics using the given parent statistic for this expression.

fn get_properties( &self, _children: &[ExprProperties], ) -> Result<ExprProperties, DataFusionError>

Calculates the properties of this PhysicalExpr based on its children’s properties (i.e. order and range), recursively aggregating the information from its children. In cases where the PhysicalExpr has no children (e.g., Literal or Column), these properties should be specified externally, as the function defaults to unknown properties.

fn snapshot(&self) -> Result<Option<Arc<dyn PhysicalExpr>>, DataFusionError>

Take a snapshot of this PhysicalExpr, if it is dynamic.

fn snapshot_generation(&self) -> u64

Returns the generation of this PhysicalExpr for snapshotting purposes. The generation is an arbitrary u64 that can be used to track changes in the state of the PhysicalExpr over time without having to do an exhaustive comparison. This is useful to avoid unnecessary computation or serialization if there are no changes to the expression. In particular, dynamic expressions that may change over time; this allows cheap checks for changes. Static expressions that do not change over time should return 0, as does the default implementation. You should not call this method directly as it does not handle recursion. Instead use snapshot_generation to handle recursion and capture the full state of the PhysicalExpr.

fn is_volatile_node(&self) -> bool

Returns true if the expression node is volatile, i.e. whether it can return different results when evaluated multiple times with the same input.

impl Eq for TryCastExpr