Enum datafusion::logicalplan::Expr

pub enum Expr {
    Alias(Box<Expr>, String),
    Column(usize),
    UnresolvedColumn(String),
    Literal(ScalarValue),
    BinaryExpr {
        left: Box<Expr>,
        op: Operator,
        right: Box<Expr>,
    },
    Not(Box<Expr>),
    IsNotNull(Box<Expr>),
    IsNull(Box<Expr>),
    Cast {
        expr: Box<Expr>,
        data_type: DataType,
    },
    Sort {
        expr: Box<Expr>,
        asc: bool,
        nulls_first: bool,
    },
    ScalarFunction {
        name: String,
        args: Vec<Expr>,
        return_type: DataType,
    },
    AggregateFunction {
        name: String,
        args: Vec<Expr>,
        return_type: DataType,
    },
    Wildcard,
}

Relation expression

Variants

Alias(Box<Expr>, String)

An aliased expression

Column(usize)

index into a value within the row or complex value

UnresolvedColumn(String)

Reference to column by name

Literal(ScalarValue)

literal value

BinaryExpr

binary expression e.g. "age > 21"

Fields of BinaryExpr

left: Box<Expr>

Left-hand side of the expression

op: Operator

The comparison operator

right: Box<Expr>

Right-hand side of the expression

Not(Box<Expr>)

unary NOT

IsNotNull(Box<Expr>)

unary IS NOT NULL

IsNull(Box<Expr>)

unary IS NULL

Cast

cast a value to a different type

Fields of Cast

expr: Box<Expr>

The expression being cast

data_type: DataType

The DataType the expression will yield

Sort

sort expression

Fields of Sort

expr: Box<Expr>

The expression to sort on

asc: bool

The direction of the sort

nulls_first: bool

Whether to put Nulls before all other data values

ScalarFunction

scalar function

Fields of ScalarFunction

name: String

Name of the function

args: Vec<Expr>

List of expressions to feed to the functions as arguments

return_type: DataType

The DataType the expression will yield

AggregateFunction

aggregate function

Fields of AggregateFunction

name: String

Name of the function

args: Vec<Expr>

List of expressions to feed to the functions as arguments

return_type: DataType

The DataType the expression will yield

Wildcard

Wildcard

Implementations

impl Expr

pub fn get_type(&self, schema: &Schema) -> Result<DataType>

Find the DataType for the expression

pub fn cast_to(&self, cast_to_type: &DataType, schema: &Schema) -> Result<Expr>

Perform a type cast on the expression value.

Will Err if the type cast cannot be performed.

pub fn eq(&self, other: &Expr) -> Expr

Equal

pub fn not_eq(&self, other: &Expr) -> Expr

Not equal

pub fn gt(&self, other: &Expr) -> Expr

Greater than

pub fn gt_eq(&self, other: &Expr) -> Expr

Greater than or equal to

pub fn lt(&self, other: &Expr) -> Expr

Less than

pub fn lt_eq(&self, other: &Expr) -> Expr

Less than or equal to

pub fn not(&self) -> Expr

Not

pub fn alias(&self, name: &str) -> Expr

Alias

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Expr

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

Formats the value using the given formatter.

impl PartialEq<Expr> for Expr

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl StructuralPartialEq for Expr