Is it possible to specify condition in Count()?

Question

Is it possible to specify a condition in Count()? I would like to count only the rows that have, for example, "Manager" in the Position column.

I want to do it in the count statement, not using WHERE; I'm asking about it because I need to count both Managers and Other in the same SELECT (something like Count(Position = Manager), Count(Position = Other)) so WHERE is no use for me in this example.

Answer 1

If you can't just limit the query itself with a where clause, you can use the fact that the count aggregate only counts the non-null values:

select count(case Position when 'Manager' then 1 else null end)
from ...

You can also use the sum aggregate in a similar way:

select sum(case Position when 'Manager' then 1 else 0 end)
from ...

Answer 2

Assuming you do not want to restrict the rows that are returned because you are aggregating other values as well, you can do it like this:

select count(case when Position = 'Manager' then 1 else null end) as ManagerCount
from ...

Let's say within the same column you had values of Manager, Supervisor, and Team Lead, you could get the counts of each like this:

select count(case when Position = 'Manager' then 1 else null end) as ManagerCount,
    count(case when Position = 'Supervisor' then 1 else null end) as SupervisorCount,
    count(case when Position = 'Team Lead' then 1 else null end) as TeamLeadCount,
from ...