Which three statements are true

Which three statements are true regarding subqueries? (Choose three.)

A.Subqueries can contain GROUP BY and ORDER BY clauses.

B.Main query and subquery can get data from different tables.

C.Main query and subquery must get data from the same tables.

D.Subqueries can contain ORDER BY but not the GROUP BY clause.

E.Only one column or expression can be compared between the main query and subquery. 

F.Multiple columns or expressions can be compared between the main query and subquery.

答案：ABF

解析：c和b相互矛盾，主查询和子查询可以访问不同的表，排除C，

a和d相互矛盾，子查询可以包括group by和order by 排除D，

e和f相互矛盾，可以有多个列和表达式能够比较，排除E