Method group_expr_len

datafusion/expr/src/logical_plan/plan.rs:3697–3699

Get the length of the group by expression in the output schema This is not simply group by expression length. Expression may be GroupingSet, etc. In these case we need to get inner expression lengths.

(&self)

    /// This is not simply group by expression length. Expression may be
    /// GroupingSet, etc. In these case we need to get inner expression lengths.
    pub fn group_expr_len(&self) -> Result<usize> {
        grouping_set_expr_count(&self.group_expr)
    }

    /// Returns the data type of the grouping id.
    ///