Question

TIA for any help/advice/further reading.

I’m trying to make SQLDev do a count of how many packages customers have had and then only show the top 10 of those results.

So I have this….

    select  pickup_customer , count (pickup_customer)
from 
( select pickup_customer, count (pickup_customer)
    from manifest
   order by count (pickup_customer) desc ) 
 where ROWNUM <= 10
 group by pickup_customer
 order by count (pickup_customer) desc

With that I’m getting ‘Not a single group function’ and I can’t figure out where it’s gone wrong. Probably very simple fix, I just can’t see it right now!

EDIT: I have tried this code but am getting a ‘missing right parenthesis ‘ error now!

select  pickup_customer , count (pickup_customer)
from 
(select pickup_customer, count (pickup_customer) --sub-query which pre-orders the results for rownum to then limit.
    from manifest
   order by count (pickup_customer) desc 
   group by pickup_customer)
 where ROWNUM <= 10    -- limits the results to be only the top 10

Answer 1

The following query should work.

SELECT pickup_customer, COUNT (pickup_customer)
FROM enrollment
WHERE ROWNUM <= 10
GROUP BY pickup_customer
ORDER BY COUNT (pickup_customer) DESC