（18）Examine the structure of the PROMOTIONS table:

The management wants to see a report of unique promotion costs in each promotion category. Which query would achieve the required result?

A. SELECT DISTINCT promo_cost, promo_category FROM promotions;

B. SELECT promo_category, DISTINCT promo_cost FROM promotions;

C. SELECT DISTINCT promo_cost, DISTINCT promo_category FROM promotions;

D. SELECT DISTINCT promo_category, promo_cost FROM promotions ORDER BY 1;

答案：（D）

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Oracle Certificate Profession 1Z0-051-18