Question

What will be the opposite of inner join? For a table table Person (int PersonId, varchar PersoName, int AddrId), I want to know the rows in Person with bad AddrId which don’t have a row in the Address table.

Answer 1

What will be the opposite of inner join?

An OUTER join, which can be of three options:

• LEFT
• RIGHT
• FULL

This is a good visual representation of JOINs

I want to know the rows in Person with bad AddrId which don’t have a row in the Address table.

Using LEFT JOIN / IS NULL

SELECT p.*
FROM PERSON p
LEFT JOIN ADDRESS a ON a.addrid = p.addrid
WHERE a.addrid IS NULL;

Using NOT EXISTS

SELECT p.*
FROM PERSON p
WHERE NOT EXISTS (
    SELECT NULL
    FROM ADDRESS a
    WHERE a.addrid = p.addrid
);

Using NOT IN

SELECT p.*
FROM PERSON p
WHERE p.addrid NOT IN (
    SELECT a.addrid
    FROM ADDRESS a
);