Left outer join not showing unmatched pairs Oracle SQL

I have a table like this, let’s call it main

location	item	price
l1	item1	3.00
l1	item2	1.00
l2	item1	3.00
l2	item2	1.50
l2	item3	2.00
l3	item4	5.00
l3	item5	5.00

and a separate table, call it items

items
item 1
item 2
item 3
item 5
item 4
item 5
item 6

and am currently trying to join the two together with this

with main as (subquery to create main), 
     items as (select distinct items from main)
select i.items, m.*
from items i 
left join main m on i.items = m.items
order by m.location, i.items

And my desired result is

i.items	location	item	price
item1	l1	item1	3.00
item2	l1	item2	1.00
item3	l1	null	null
item4	l1	null	null
item5	l1	null	null
item6	l1	null	null
item1	l2	item1	3.00
item2	l2	item2	1.50
item3	l2	item3	2.00
item4	l2	null	null
item5	l2	null	null
item6	l2	null	null
item1	l3	null	null
item2	l3	null	null
item3	l3	null	null
item4	l3	item4	5.00
item5	l3	item5	5.00
item6	l3	null	null

However, it ends up just looking like the main table but sorted, with none of the unmatched items being shown. Am I doing something wrong?

Answer

It seems you want one result row per item and location whether or not that pair has entries in the main table. So first generate these rows with a cross join. Only then outer join your original data.

with main as (<subquery to create main>), 
     items as (select distinct item from main),
     locations as (select distinct location from main)
select i.item, l.location, m.price
from items i 
cross join locations l
left join main m on m.item = i.item and m.location = l.location
order by i.item, l.location;