Function infer_join_predicates 

fn infer_join_predicates(
    join: &Join,
    predicates: &[Expr],
    on_filters: &[Expr],
) -> Result<Vec<Expr>>

Extracts any equi-join join predicates from the given filter expressions.

Parameters

• join the join in question

• predicates the pushed down filter expression

• on_filters filters from the join ON clause that have not already been identified as join predicates