Answers for "select distinct and inner join"

select join distinct

$items = DB::table('item')->select('item_name')->distinct()->get();

inner join distinct

SELECT valueC
FROM C
INNER JOIN
(
    SELECT DISTINCT lookupC
    FROM B INNER JOIN
    (
        SELECT DISTINCT lookupB
        FROM A
    ) 
    A2 ON B.id = A2.lookupB
) 
B2 ON C.id = B2.lookupC