Struct datafusion_functions::string::concat::ConcatFunc

pub struct ConcatFunc { /* private fields */ }

Implementations

impl ConcatFunc

pub fn new() -> Self

Trait Implementations

impl Debug for ConcatFunc

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

Formats the value using the given formatter.

impl Default for ConcatFunc

fn default() -> Self

Returns the “default value” for a type.

impl ScalarUDFImpl for ConcatFunc

fn invoke(&self, args: &[ColumnarValue]) -> Result<ColumnarValue>

Concatenates the text representations of all the arguments. NULL arguments are ignored. concat(‘abcde’, 2, NULL, 22) = ‘abcde222’

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

Simplify the concat function by

1. filtering out all null literals
2. concatenating contiguous literal arguments

For example: concat(col(a), 'hello ', 'world', col(b), null) will be optimized to concat(col(a), 'hello world', col(b))

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 the function’s Signature for information about what input types are accepted and the function’s Volatility.

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

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

fn return_type_from_exprs( &self, _args: &[Expr], _schema: &dyn ExprSchema, arg_types: &[DataType] ) -> Result<DataType, DataFusionError>

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

fn invoke_no_args( &self, _number_rows: usize ) -> Result<ColumnarValue, DataFusionError>

Invoke the function without args, instead the number of rows are provided, returning the appropriate result.

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

Returns any aliases (alternate names) for this function.

fn monotonicity(&self) -> Result<Option<Vec<Option<bool>>>, DataFusionError>

This function specifies monotonicity behaviors for User defined scalar functions.

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 Setting this to true prevents certain optimizations such as common subexpression elimination