BPSC TRE – DBMS: Relational Algebra, Calculus, SQL & Relational Operators

Question 21

MCQ · Single Correct 1 mark

What is the essential difference between WHERE and HAVING clauses in an SQL query?

A (A) WHERE filters individual tuples, while HAVING filters groups of tuples B (B) Aggregate functions cannot be used directly in a WHERE clause, but can be used in a HAVING clause C (C) WHERE is applied before GROUP BY, while HAVING is applied after GROUP BY D (D) More than one of the above E (E) None of the above

Question 22

MCQ · Single Correct 1 mark

Which of the following is NOT a built-in SQL standard aggregate function?

A (A) AVG() B (B) COUNT() C (C) CONCAT() D (D) More than one of the above E (E) None of the above

Question 23

MCQ · Single Correct 1 mark

What does the SQL expression COUNT(*) return?

A (A) The total number of rows in the table, including rows with NULL values and duplicate values B (B) The total number of rows excluding NULL values C (C) The number of distinct rows only D (D) More than one of the above E (E) None of the above

Question 24

MCQ · Single Correct 1 mark

How does the aggregate function AVG(Salary) handle NULL values present in the Salary column?

A (A) It automatically ignores NULL values in both the sum numerator and count denominator B (B) It treats NULL as numeric 0 in the computation C (C) It returns NULL immediately if any single row contains NULL D (D) More than one of the above E (E) None of the above

Question 25

MCQ · Single Correct 1 mark

Which keyword is used in a SELECT statement to eliminate duplicate rows from the query result set?

A (A) DISTINCT B (B) UNIQUE C (C) ALL D (D) More than one of the above E (E) None of the above