Method new

src/sql/src/plan/lowering.rs:77–79

(inner: BTreeMap<ColumnRef, usize>)

    }

    fn new(inner: BTreeMap<ColumnRef, usize>) -> ColumnMap {
        ColumnMap { inner }
    }

    fn get(&self, col_ref: &ColumnRef) -> usize {
        if col_ref.level == 0 {