如何用SQL语句查出该表中 不为空的值得数量

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）

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;

select count(*) from xxx where xxx is not null

select count(*) from table_name where studentLoginId is not null

select count(*) from table_name where parentLoginId is not null

select count(*) from (
select * from table_name where studentLoginId is not null
union all
select * from table_name where parentLoginId is not null
) total

select count(*) from xxx where xxx is not null

select count(*) from tb where studentLoginID is not null

或者

select count(*) from tb where nvl(studentLoginID,0) <> 0