Hi – in the 1 day retention lesson (https://www.codecademy.com/courses/sql-analyzing-business-metrics/lessons/common-metrics/exercises/1d-retention-iii?action=lesson_resume&link_content_target=interstitial_undefined)
I want to understand better the syntax of the distinct function in
select date(g1.created_at) as dt, round(100 * count(distinct g2.user_id) / count(distinct g1.user_id)) as retention from gameplays as g1 left join gameplays as g2 on g1.user_id = g2.user_id and date(g1.created_at) = date(datetime(g2.created_at, '-1 day')) group by 1 order by 1 limit 100;
I originally did it with (count(distinct(g2.user_id)) but was getting errors. Is the space completely interchangeable with the parenthetical, or is it used specifically in cases where there is a join?