Enum GroupingSet

datafusion/expr/src/expr.rs:1418–1425

/// for Apache Spark definition.
#[derive(Clone, PartialEq, Eq, PartialOrd, Hash, Debug)]
pub enum GroupingSet {
    /// Rollup grouping sets
    Rollup(Vec<Expr>),
    /// Cube grouping sets
    Cube(Vec<Expr>),
    /// User-defined grouping sets
    GroupingSets(Vec<Vec<Expr>>),
}

impl GroupingSet {
    /// Return all distinct exprs in the grouping set. For `CUBE` and `ROLLUP` this