Question

Which join refers to join records from the write table that have no matching key in the left table are include in the result set:

(a) Left outer join

(b) Right outer join

(c) Full outer join

(d) Half outer join

This question was addressed to me in an online interview.

The query is from Join Operations in chapter Query Processing Techniques of Database Management

Answer 1

Right choice is (b) Right outer join

The explanation is: A right outer join will return all the rows that an inner join returns plus one row for each of the other rows in the second table that did not have a match in the first table. It is the same as a left outer join with the tables specified in the opposite order.