12c OCP考试专项 [1z0-071]-Q22: 小计合计（2020.06.18）

which group by clause must be added so the query returns the result shown?

A. group by ch.channel_type,t.month,rollup(co.country_code);
B. group by ch.channel_type,rollup(t.month,co.country_code);
C. group by CUBE(ch.channel_type,t.month,co.country_code);
D. group by ch.channel_type,t.month,co.country_code;

Answer：B

Explanation:

官方文档例题 Example 20-2 Partial ROLLUP 小计合并

提示：答案为个人理解和解答，难免有错，也欢迎大家及时指正。