Question

I have a table of users containing the following columns:

| User_ID  (int) | Name (varchar) |   Age (int)  |  Experience_Level (int) |

I would like to create an sql query to output all of the IDs of people who are not unique in the combination of age and experience.

My code so far:

SELECT Count(*), User_ID FROM Users 
GROUP BY Age,Experience_Level
HAVING Count(*) > 1

Obviously this is incomplete, This will group the non-unique users but it will not tell me all of their User_IDs.

Thanks in advance for your help!

Answer 1

Here’s a negated logic query:

SELECT *
FROM Users
WHERE UserID not in
(
SELECT MIN(UserID)
FROM Users
GROUP BY Age, Experience_Level
HAVING COUNT(*) = 1
)