Which two statements are true about the results of using the INTERSECT operator in compound queres?
A) Reversing the order of the intersected tables can sometimes affect the output.
B) Column names in each SELECT in the compound query can be dfferent.
C) INTERSECT returns rows common to both sides of the compound query.
D) The number of columns in each SELECT in the compound query can be dfferent.
E) INTERSECT ignores NULLs
Answer：：BC
(解析：intersect 会以第一个查询的第一个列的值进行排序输出，由于求的是交集，所以表的查询顺序可以不分先后;列的名字可以不一样，但是数据类型必须匹配。)
原文：https://blog.51cto.com/13854012/2451746