COUNT() over result of Except

Question

I have a query like:

SELECT
    id
FROM
    table1
INNER JOIN
    ...
WHERE
    ...
    AND eventtype IN (2000120, 2000121, 2000122, 2000123, 2000130)

EXCEPT

SELECT
    id
FROM
    table1
INNER JOIN
    ...
WHERE
    ...
    AND eventtype IN (2000123,2000130,2000134,2000135)

Note that the queries are both identical except the last where-clause.

I would now like to count the number of records returned by this above query.

How to?

Many thanks

Answer 1

use COUNT and wrap it inside a SUBQUERY

SELECT COUNT(ID)
FROM (
        SELECT id
        FROM table1
        INNER JOIN...
        WHERE...
                AND eventtype IN ( 2000120, 2000121, 2000122, 2000123, 2000130 )
        EXCEPT
        SELECT id
        FROM table1
        INNER JOIN...
        WHERE...
                AND eventtype IN ( 2000123, 2000130, 2000134, 2000135 )
        ) s