Function is_lateral_join

datafusion/sql/src/relation/join.rs:193–212

Returns `true` if the given [`Join`] is lateral.

(join: &Join)

/// Returns `true` if the given [`Join`] is lateral.
pub(crate) fn is_lateral_join(join: &Join) -> Result<bool> {
    let is_lateral_syntax = is_lateral(&join.relation);
    let is_apply_syntax = match join.join_operator {
        JoinOperator::FullOuter(..)
        | JoinOperator::Right(..)
        | JoinOperator::RightOuter(..)
        | JoinOperator::RightAnti(..)
        | JoinOperator::RightSemi(..)
            if is_lateral_syntax =>
        {
            return not_impl_err!(
                "LATERAL syntax is not supported for \
                 FULL OUTER and RIGHT [OUTER | ANTI | SEMI] joins"
            );
        }
        JoinOperator::CrossApply | JoinOperator::OuterApply => true,
        _ => false,
    };
    Ok(is_lateral_syntax || is_apply_syntax)
}