Getting number of certain days-of-the-week (weekend) from interval in PostgreSQL

Question

Given 2 timestamps in postgres, how do you calculate the time difference without counting whole Saturdays and Sundays?

OR

How do you count the number of Satu

Answer 1

You might find this really helpful:

CREATE OR REPLACE FUNCTION working_days(date, date) RETURNS INT AS
$$
SELECT COUNT(days)::INT
    FROM generate_series($1, $2, '1 day') AS days
    WHERE EXTRACT(DOW FROM days) NOT IN(0, 6);
$$
LANGUAGE 'sql' IMMUTABLE STRICT;