Method new_bounds

datafusion/expr/src/window_frame.rs:209–246

Initializes window frame from units (type), start bound and end bound.

(
        units: WindowFrameUnits,
        start_bound: WindowFrameBound,
        end_bound: WindowFrameBound,
    )

    /// Initializes window frame from units (type), start bound and end bound.
    pub fn new_bounds(
        units: WindowFrameUnits,
        start_bound: WindowFrameBound,
        end_bound: WindowFrameBound,
    ) -> Self {
        let causal = match units {
            WindowFrameUnits::Rows => match &end_bound {
                WindowFrameBound::Following(value) => {
                    if value.is_null() {
                        // Unbounded following
                        false
                    } else {
                        let zero = ScalarValue::new_zero(&value.data_type());
                        zero.map(|zero| value.eq(&zero)).unwrap_or(false)
                    }
                }
                _ => true,
            },
            WindowFrameUnits::Range | WindowFrameUnits::Groups => match &end_bound {
                WindowFrameBound::Preceding(value) => {
                    if value.is_null() {
                        // Unbounded preceding
                        true
                    } else {
                        let zero = ScalarValue::new_zero(&value.data_type());
                        zero.map(|zero| value.gt(&zero)).unwrap_or(false)
                    }
                }
                _ => false,
            },
        };
        Self {
            units,
            start_bound,
            end_bound,
            causal,
        }
    }

    /// Regularizes the ORDER BY clause of the window frame.
    pub fn regularize_order_bys(&self, order_by: &mut Vec<Sort>) -> Result<()> {