Apply different Adjustment Factor for different date range

I have a Table with SalesPerson and Sales for different dates. I have another table where I have SalesPerson and multiple date ranges where different Adjustment factor needs to be applied.

I can do this with a case statement when there is one or no row for the person in the adjustment factor table. But I am not sure how to loop through different date ranges for same salesperson

    select a.date, a.salesperson, a.sales, b.adjustmentfactor, 
    case when a.date between b.startdate and b.enddate then b.adjustmentfactor 
    else 1 end realadjfactor,
    a.sales * case when a.date between b.startdate and b.enddate then 
    b.adjustmentfactor else 1 end realsales
    from sales a left join adjfactor b on a.salesperson = b.salesperson

Answer

Do you just want a join?

select s.date, s.salesperson, s.sales, 
       coalesce(af.realadjfactor, 1) * s.sales as adjustedsales,
       coalesce(af.realadjfactor, 1) as adjfactor
from sales s left join
     adjfactor af
     on s.salesperson = af.salesperson and
        s.date between af.startdate and af.enddate;