LeetCode 1355: Activity Participants [SQL]

Solution and walkthrough of leetcode database problem 1355: Activity Participants. I'm using MySQL but this solution should work in any SQL dialect such as PostgreSQL SQL Server, etc.

Playlists:

[daniellesong]

Hey Frederik, my code doesn't work and report error: unknown column 'activitynumber' in having clause, can you please tell why? Thank you
SELECT a.activity AS activity FROM
(SELECT activity, COUNT(DISTINCT name) AS activitynumber FROM Friends
GROUP BY activity) a
HAVING AND

[kartiikss]

Hi Fred, Thank you for your video. Can you tell me if my solution would work?

SELECT activity
FROM Friends
GROUP BY activity
HAVING COUNT(*) NOT IN ((SELECT MAX(COUNT(*) as m)
FROM Friends
GROUP BY activity)
UNION
(SELECT MIN(COUNT(*) as m)
FROM Friends
GROUP BY activity))

Thank you for your help!

[vaibhavaneja]

Hi,
I am new to SQL.
Can anyone please let me know if below mentioned code will work or not. If not, why?
SELECT activity
FROM friends
WHERE activity NOT IN ( SELECT activity, max(id), min(id) FROM friends
GROUP BY
Activity)
Would really appreciate you help!
Thanks

[LifeofTF]

Hey Frederik, I don't have leetcode premium but would love to know if this works:
WITH temp AS (
SELECT
activity,
COUNT(*) AS act_cnt
FROM Friends
GROUP BY activity
)

SELECT
activity
FROM temp
WHERE act_cnt != MAX(act_cnt) AND act_cnt != MIN(act_cnt)

[MJ-qtfs]

Hey Frederik, Can you please also do leetcode #1454. Active Users?

[maheshodedra]

Hey Fred, Firstly thanks for the video.

Can you please check of below code work and if not can you please let me know the correction of it !!

SELECT activity FROM friends GROUP BY activity HAVING COUNT(*) > MIN(COUNT(*)) AND COUNT(*) < MAX(COUNT(*))

Looking forward to your response :-)