I was able to complete the challenge, but I was curious why COUNT(watch_duration_in_minutes) works and not COUNT(duration). As far as I understand, the ROUND command doesn’t actually change the data in the table, so how was COUNT able to count the rounded values when I specified the original column name, and not the renamed round results?
In other words, why is the below example right?
Correct:
SELECT ROUND(watch_duration_in_minutes, 0) AS duration, COUNT(watch_duration_in_minutes) AS “count” FROM watch_history;
Not correct:
SELECT ROUND(watch_duration_in_minutes, 0) AS duration, COUNT(duration) AS “count” FROM watch_history;