Why is "items" not specified after the from statement after customers?

Question

SELECT customers.name, items.name
FROM customers (, items?)
LEFT OUTER JOIN items ON customers.id=seller_id

Answer 1

it's a different mode for writing join statement between two table; the following instruction use a sequence of table name to put in join after FROM (the symbol + is associated to key of that table which values doesn't have correspondence)
SELECT customers.name, items.name
FROM customers , items
WHERE customers.id=items.seller_id(+)

this other statement instead use LEFT OUTER JOIN for the same result

SELECT customers.name, items.name
FROM customers
LEFT OUTER JOIN items ON customers.id=items.seller_id