Function find_unnest_node_within_select

datafusion/sql/src/unparser/utils.rs:76–95

Recursively searches children of [LogicalPlan] to find Unnest node if exist

(plan: &LogicalPlan)

/// Recursively searches children of [LogicalPlan] to find Unnest node if exist
pub(crate) fn find_unnest_node_within_select(plan: &LogicalPlan) -> Option<&Unnest> {
    // Note that none of the nodes that have a corresponding node can have more
    // than 1 input node. E.g. Projection / Filter always have 1 input node.
    let input = plan.inputs();
    let input = if input.len() > 1 {
        return None;
    } else {
        input.first()?
    };

    if let LogicalPlan::Unnest(unnest) = input {
        Some(unnest)
    } else if let LogicalPlan::TableScan(_) = input {
        None
    } else if let LogicalPlan::Projection(_) = input {
        None
    } else {
        find_unnest_node_within_select(input)
    }
}

/// Recursively searches children of [LogicalPlan] to find Unnest node if exist
/// until encountering a Relation node with single input