Using the CUSTOMERS table, you need to generate a report that shows 50% of each credit
amount in each income level. The report should NOT show any repeated credit amounts in each
income level. Which query would give the required result?
A.
SELECT cust_income_level, DISTINCT cust_credit_limit * 0.50 AS “50% Credit Limit” FROM customers;
B.
SELECT DISTINCT cust_income_level, DISTINCT cust_credit_limit * 0.50 AS “50% Credit Limit”
FROM customers;
C.
SELECT DISTINCT cust_income_level ‘ ‘ cust_credit_limit * 0.50 AS “50% Credit Limit” FROM customers;
D.
SELECT cust_income_level ‘ ‘ cust_credit_limit * 0.50 AS “50% Credit Limit” FROM customers;
Explanation:
Duplicate Rows
Unless you indicate otherwise, SQL displays the results of a query without eliminating the duplicate rows.
To eliminate duplicate rows in the result, include the DISTINCT keyword in the SELECT clause
immediately after the SELECT keyword.
You can specify multiple columns after the DISTINCT qualifier. The DISTINCT qualifieraffects all the selected columns, and the result is every distinct combination of the columns.