题解 | #查找除复旦大学的用户信息#
用where过滤空值练习
http://www.nowcoder.com/practice/08c9846a423540319eea4be44e339e35
# select device_id,gender,age,university from user_profile where age is not null;
select device_id,gender,age,university from user_profile where age!='null';