如何用SQL语句查出该表中 不为空的值得数量

Question

如何用SQL语句查出该表中 不为空的值得数量
（studentLoginId不为空的有几个，parentLoginId不为空的有几个，它们的和）

Answer 1

select (select count(1) from table where studentLoginId is null) scount,
(select count(1) from table where parentLoginId is null)) pcount,

(select count(1) from table where studentLoginId is null)+(select count(1) from table where parentLoginId is null)) suncount
from dual;