SELECT ct.name,.name FROM customers ct, items AS it WHERE it.seller_id=.id;

• WHERE
• SELECT students.name，
• universities.name
• students.university_id=universities.id;
• FROM students，
• universities

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

• SELECT students.names
• universities.names
• ON students.university_id=universities.id;
• FROM students
• RIGHT OUTER JOIN universities