Struct LagFunction 

pub struct LagFunction { /* private fields */ }

LAG window function

Returns the value from a row that is offset rows before the current row within the partition. If there is no such row, returns the default value.

Implementations

impl LagFunction

pub fn new(offset: usize, default_value: Value) -> Self

Create a new LAG function with the specified offset and default value

pub fn with_offset(offset: usize) -> Self

Create a new LAG function with offset 1 and NULL default

Trait Implementations

impl Default for LagFunction

fn default() -> LagFunction

Returns the “default value” for a type.

impl WindowFunction for LagFunction

fn name(&self) -> &str

Get the function name

fn info(&self) -> FunctionInfo

Get function information

fn process( &self, partition: &[Value], _order_by: &[Value], current_row: usize, ) -> Result<Value>

Process the window function

fn clone_box(&self) -> Box<dyn WindowFunction>

Clone the function into a new instance