I have a typical Persons table and an Orders table defined in such a way that I can do JOIN query as the following to return Orders for all Persons.
SELECT Persons.LastName, Persons.FirstName, Orders.OrderNo FROM Persons INNER JOIN Orders ON Persons.id=Orders.Person_id
The question is, how do I write a statement that would return all Persons with NO Orders?
I'm using mysql.
Thank all in advance.
You may want to use
LEFT JOIN and
SELECT Persons.LastName, Persons.FirstName FROM Persons LEFT JOIN Orders ON Persons.id = Orders.Person_id WHERE Orders.Person_id IS NULL;
The result of a left join always contains all records of the "left" table (Persons), even if the join-condition does not find any matching record in the "right" table (Orders). When there is no match, the columns of the "right" table will
NULL in the result set.