How to do a count on a union query

Question

I have the following query:

select distinct profile_id from userprofile_...

union

select distinct profile_id from productions_...

How wou

Answer 1

These will not work if in one of the COUNT(*) the result is equals to 0.

This will be better:

SELECT SUM(total)
FROM
(
    select COUNT(distinct profile_id) AS total
    from userprofile_...

    union all

    select COUNT(distinct profile_id) AS total
    from productions_...
) x