Function update_join_on 

pub fn update_join_on(
    proj_left_exprs: &[(Column, String)],
    proj_right_exprs: &[(Column, String)],
    hash_join_on: &[(Arc<dyn PhysicalExpr>, Arc<dyn PhysicalExpr>)],
    left_field_size: usize,
) -> Option<Vec<(Arc<dyn PhysicalExpr>, Arc<dyn PhysicalExpr>)>>

Tries to update the equi-join Column’s of a join as if the input of the join was replaced by a projection.