题解 | #用where过滤空值练习#

--过滤空值的三种方法：

--(1) Where 列名 is not null
select device_id, gender, age, university
from user_profile
where age is not null

--(2) Where 列名 != 'null'
select device_id, gender, age, university
from user_profile
where age != 'null'

--(3) Where 列名 <> 'null'
select device_id, gender, age, university
from user_profile
where age <> 'null'