Question

What is the function of the except operation?

(a) It excludes all the results present in both the queries

(b) It includes the results of the second query but excludes the results of the first query

(c) It includes the results of the first query but excludes the results of the second query

(d) It includes all the results of both queries but removes duplicates

I had been asked this question in an interview for internship.

I would like to ask this question from Set Operations topic in division Introduction to Relational Model and Sql of RDBMS

Answer 1

Right answer is (c) It includes the results of the first query but excludes the results of the second query

For explanation: The except operation includes the results of the first query but excludes the results of the second query. It automatically eliminates duplicates but if we want to retain duplicates we must use except all in place of except.