Contents of the BOOKS table

-Based on the contents of the BOOKS table,which of the following is a valid SQL statement?
A) SELECT pubid,AVERAGE(retail-cost)"Average Profit" FROM books;
B) SELECT pubid,AVERAGE(retail-cost)"Average Profit" FROM books GROUP BY pubid;
C) SELECT pubid,AVG(retail-cost)"Average Profit" FROM books GROUP BY pubid;
D) SELECT pubid,AVG(retail-cost)"Average Profit" FROM books HAVING retail-cost 25;

Question

Contents of the BOOKS table​
 
-Based on the contents of the BOOKS table,which of the following is a valid SQL statement?​
A) ​SELECT pubid,AVERAGE(retail-cost)"Average Profit" FROM books; 
B) SELECT pubid,AVERAGE(retail-cost)"Average Profit" FROM books GROUP BY pubid;​ 
C) ​SELECT pubid,AVG(retail-cost)"Average Profit" FROM books GROUP BY pubid; 
D) ​SELECT pubid,AVG(retail-cost)"Average Profit" FROM books HAVING retail-cost > 25;

Quizplus · Accepted Answer

The correct SQL statement would require the use of an aggregate function (AVG) and a GROUP BY clause, as we want to calculate the average profit for each publisher (pubid). Option C has the correct syntax, as it uses AVG and GROUP BY pubid to group the results by publisher. Option A is incorrect because it does not include the GROUP BY clause, which is required when using aggregate functions. Option B is almost correct, but it includes quotation marks around the alias "Average Profit," which would cause an error in some database systems. Option D is incorrect because it includes a HAVING clause, which is used to filter results after the GROUP BY clause has been applied, rather than to calculate an aggregate function by a specific threshold.

Contents of the BOOKS Table​

Contents of the BOOKS Table