Function range 

pub fn range(
    stats: Option<&ColumnStats>,
    low: Option<&Value>,
    high: Option<&Value>,
    _lo_incl: bool,
    _hi_incl: bool,
) -> f64

col >= low AND col <= high (with both bounds optional). When low is None the lower side is open at −∞; same for high and +∞. lo_incl / hi_incl control whether the boundary itself is included (currently a near-no-op since selectivity estimation is approximate at the boundary, but kept in the signature so the planner can pass the parser’s intent through).