Struct ArrowCastFunc 

pub struct ArrowCastFunc { /* private fields */ }

Implements casting to arbitrary arrow types (rather than SQL types)

Note that the arrow_cast function is somewhat special in that its return depends only on the value of its second argument (not its type)

It is implemented by calling the same underlying arrow cast kernel as normal SQL casts.

For example to cast to int using SQL (which is then mapped to the arrow type Int32)

select cast(column_x as int) ...

Use the arrow_cast function to cast to a specific arrow type

For example

select arrow_cast(column_x, 'Float64')

Implementations

impl ArrowCastFunc

pub fn new() -> Self

Trait Implementations

impl Debug for ArrowCastFunc

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

Formats the value using the given formatter.

impl Default for ArrowCastFunc

fn default() -> Self

Returns the “default value” for a type.

impl Hash for ArrowCastFunc

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 for ArrowCastFunc

fn eq(&self, other: &ArrowCastFunc) -> 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 ScalarUDFImpl for ArrowCastFunc

fn as_any(&self) -> &dyn Any

Returns this object as an Any trait object

fn name(&self) -> &str

Returns this function’s name

fn signature(&self) -> &Signature

Returns a Signature describing the argument types for which this function has an implementation, and the function’s Volatility.

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

DataType returned by this function, given the types of the arguments.

fn return_field_from_args(&self, args: ReturnFieldArgs<'_>) -> Result<FieldRef>

What type will be returned by this function, given the arguments?

fn invoke_with_args(&self, _args: ScalarFunctionArgs) -> Result<ColumnarValue>

Invoke the function returning the appropriate result.

fn simplify( &self, args: Vec<Expr>, info: &dyn SimplifyInfo, ) -> Result<ExprSimplifyResult>

Optionally apply per-UDF simplification / rewrite rules.

fn documentation(&self) -> Option<&Documentation>

Returns the documentation for this Scalar UDF.

fn aliases(&self) -> &[String]

Returns any aliases (alternate names) for this function.

fn display_name(&self, args: &[Expr]) -> Result<String, DataFusionError>

👎Deprecated since 50.0.0: This method is unused and will be removed in a future release

Returns the user-defined display name of function, given the arguments

fn schema_name(&self, args: &[Expr]) -> Result<String, DataFusionError>

Returns the name of the column this expression would create

fn is_nullable(&self, _args: &[Expr], _schema: &dyn ExprSchema) -> bool

👎Deprecated since 45.0.0: Use return_field_from_args instead. if you use is_nullable that returns non-nullable with return_type, you would need to switch to return_field_from_args, you might have error

fn short_circuits(&self) -> bool

Returns true if some of this exprs subexpressions may not be evaluated and thus any side effects (like divide by zero) may not be encountered.

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

Computes the output Interval for a ScalarUDFImpl, given the input intervals.

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

Updates bounds for child expressions, given a known Intervals for this function.

fn output_ordering( &self, inputs: &[ExprProperties], ) -> Result<SortProperties, DataFusionError>

Calculates the SortProperties of this function based on its children’s properties.

fn preserves_lex_ordering( &self, _inputs: &[ExprProperties], ) -> Result<bool, DataFusionError>

Returns true if the function preserves lexicographical ordering based on the input ordering.

fn coerce_types( &self, _arg_types: &[DataType], ) -> Result<Vec<DataType>, DataFusionError>

Coerce arguments of a function call to types that the function can evaluate.

impl Eq for ArrowCastFunc

impl StructuralPartialEq for ArrowCastFunc