Struct WindowFunction 

pub struct WindowFunction {
    pub kind: WindowFuncKind,
    pub return_type: DataType,
    pub args: Vec<ExprImpl>,
    pub ignore_nulls: bool,
    pub partition_by: Vec<ExprImpl>,
    pub order_by: OrderBy,
    pub frame: Option<Frame>,
}

A window function performs a calculation across a set of table rows that are somehow related to the current row, according to the window spec OVER (PARTITION BY .. ORDER BY ..). One output row is calculated for each row in the input table.

Window functions are permitted only in the SELECT list and the ORDER BY clause of the query. They are forbidden elsewhere, such as in GROUP BY, HAVING and WHERE clauses.

Fields

kind: WindowFuncKind

return_type: DataType

args: Vec<ExprImpl>

ignore_nulls: bool

partition_by: Vec<ExprImpl>

order_by: OrderBy

frame: Option<Frame>

Implementations

impl WindowFunction

pub fn new( kind: WindowFuncKind, args: Vec<ExprImpl>, ignore_nulls: bool, partition_by: Vec<ExprImpl>, order_by: OrderBy, frame: Option<Frame>, ) -> RwResult<Self>

Create a WindowFunction expr with the return type inferred from func_type and types of inputs.

fn infer_return_type( kind: &WindowFuncKind, args: &mut [ExprImpl], ) -> RwResult<DataType>

Trait Implementations

impl Clone for WindowFunction

fn clone(&self) -> WindowFunction

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for WindowFunction

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

Formats the value using the given formatter.

impl Expr for WindowFunction

fn return_type(&self) -> DataType

Get the return type of the expr

fn try_to_expr_proto(&self) -> Result<ExprNode, String>

Try to serialize the expression, returning an error if it’s impossible.

fn to_expr_proto(&self) -> ExprNode

Serialize the expression. Panic if it’s impossible.

impl From<WindowFunction> for ExprImpl

fn from(o: WindowFunction) -> ExprImpl

Converts to this type from the input type.

impl Hash for WindowFunction

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 WindowFunction

fn eq(&self, other: &WindowFunction) -> 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 Eq for WindowFunction

impl StructuralPartialEq for WindowFunction