Function create_cube_physical_expr

datafusion/core/src/physical_planner.rs:1997–2039

Expand and align a CUBE expression. This is a special case of GROUPING SETS (see )

(
    exprs: &[Expr],
    input_dfschema: &DFSchema,
    input_schema: &Schema,
    execution_props: &ExecutionProps,
)

/// Expand and align a CUBE expression. This is a special case of GROUPING SETS
/// (see <https://www.postgresql.org/docs/current/queries-table-expressions.html#QUERIES-GROUPING-SETS>)
fn create_cube_physical_expr(
    exprs: &[Expr],
    input_dfschema: &DFSchema,
    input_schema: &Schema,
    execution_props: &ExecutionProps,
) -> Result<PhysicalGroupBy> {
    let num_of_exprs = exprs.len();
    let num_groups = num_of_exprs * num_of_exprs;

    let mut null_exprs: Vec<(Arc<dyn PhysicalExpr>, String)> =
        Vec::with_capacity(num_of_exprs);
    let mut all_exprs: Vec<(Arc<dyn PhysicalExpr>, String)> =
        Vec::with_capacity(num_of_exprs);

    for expr in exprs {
        null_exprs.push(get_null_physical_expr_pair(
            expr,
            input_dfschema,
            input_schema,
            execution_props,
        )?);

        all_exprs.push(get_physical_expr_pair(
            expr,
            input_dfschema,
            execution_props,
        )?)
    }

    let mut groups: Vec<Vec<bool>> = Vec::with_capacity(num_groups);

    groups.push(vec![false; num_of_exprs]);

    for null_count in 1..=num_of_exprs {
        for null_idx in (0..num_of_exprs).combinations(null_count) {
            let mut next_group: Vec<bool> = vec![false; num_of_exprs];
            null_idx.into_iter().for_each(|i| next_group[i] = true);
            groups.push(next_group);
        }
    }

    Ok(PhysicalGroupBy::new(all_exprs, null_exprs, groups, true))
}

/// Expand and align a ROLLUP expression. This is a special case of GROUPING SETS
/// (see <https://www.postgresql.org/docs/current/queries-table-expressions.html#QUERIES-GROUPING-SETS>)