FAQ: Code Challenge: Aggregate Functions - Code Challenge 9

Frequently Asked Questions SQL FAQ
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This community-built FAQ covers the “Code Challenge 9” exercise from the lesson “Code Challenge: Aggregate Functions”.

Paths and Courses
This exercise can be found in the following Codecademy content:

Web Development
Data Science

FAQs on the exercise Code Challenge 9

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SELECT MAX(watch_duration_in_minutes) AS ‘MAX Duration’, MIN (watch_duration_in_minutes) AS ‘MIN Duration’
FROM watch_history;

The above code is correct but just curious why this is wrong:

SELECT watch_duration_in_minutes AS ‘Duration’, MAX(Duration), MIN(Duration)
FROM watch_history;

1 Like
3

What if I wanted to know the user_id and watch_date of both the longest and shortest event? Can this be done in one query?

4

My instructions say to rename the results. When trying to add the AS statement it would not accept my answer. When I clicked the hint it did not have the AS statements. So why is it telling me to rename anything? Did anyone else have this issue or did I just massively over think this test?

5

I thought the same thing. I had renamed them and it was failing me. Then I noticed that the order of the MIN, MAX makes a difference. If you use MIN first it fails but MAX first succeeds, named or not.

7

Use AS. Once a column has been renamed with AS, the new name will work in the later steps in your query.

SELECT long_name AS short_name 
FROM my_table
WHERE short_name > 30;
8

Can someone explain the correct code for renaming the new columns by adding AS in the last exercise?

9

What if I want to see each user whom has recorded max(watch_duration_in_minutes) and whom has recorded minimum of it?
Is it possible in SQL??

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Hi everyone! Who could help and explain this problem?

Code is: SELECT MIN(watch_duration_in_minutes) AS ‘min’, MAX(watch_duration_in_minutes) AS ‘max’
FROM watch_history;
I’ve got the result

But I have this error: Query should return the maximum and then the minimum watch durations, in one query.

11

Ok, problem is solved. Just swapped function MAX() and MIN().
Correct code is:
SELECT MAX(watch_duration_in_minutes) AS ‘max’, MIN(watch_duration_in_minutes) AS ‘min’
FROM watch_history;

13

After run the collect query, the result appear, max and min.
Are those results different ‘user_id’(or ‘id’)?

When I tried to put ‘SELECT user_id …,’ in the first line, the result was just ‘user_id’ is added on the left. It looks like same user_id happen to have max and min at the same time?

I guess that each column shows independent results.

14

mistype, in the first line, not collect query, but correct query.
Thanks

15

Hello to every/anyone, I have a questions regarding column referencing, specifically from question 6 of this exercise

I had tried to use the following syntax for my answer, which would be correct if i simply didn’t use the column references, but is showing up as wrong when I replace the columns in the select statement with numbers. I tried tinkering with it and it boiled down to the SUM function in the SELECT statement - apparently I can reference the user_id column and I’ll get a resulting query, but once i reference the SUM column, the query fails (even without the alias). Anyone know why?

SELECT user_id, SUM(watch_duration_in_minutes) AS ‘total_minutes’
FROM watch_history
GROUP BY 1
HAVING 2 > 400;

Any help would be appreciated!

EDIT: looks like you can’t reference a column as a number if you’re using operators because SQL won’t see “2” as a reference. Can someone confirm this?

SOLVED: confirmed in next section (How to Hack Hacker News) - HAVING doesn’t support aliases so you’d need to spell out the entire aggregate function column.

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VALID FAQ covers the “Code Challenge 9” exercise from the lesson “Code Challenge